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THE CUPOLA FURNACE: 



A PRACTICAL TREATISE ON THE 



CONSTRUCTION AND MANAGEMENT 



FOUNDRY CUPOLAS. 



COMPRISING 

THE BEST METHODS OF CONSTRUCTION AND MANAGEMENT OF CUPOLAS; DIFFERENT 

SHAPED CUPOLAS; HEIGHT OF CUPOLAS; PLACING TUYERES; SHAPES OF TUYERES; 

LINING; SPARK CATCHING DEVICES; BLOWERS; BLAST PIPES; AIR GAUfiES; 

CHARGING;. DIRECTIONS FOR THE MELTING OF IRON, TIN-PLATE SCRAP, 

AND OTHER METALS IN CUPOLAS; EXPERIMENTS IN MELTING; 

WHAT A CUPOLA WILL MELT; ETC. 



EDWARD KIRK. 

PRACTICAL MOULDER AND MELTER, CONSULTING EXPERT IN MELTING. 

Author of The Founding o/ Metals, and of Numerous Papers on Cupola Practice. 



ILLUSTRATED BY SEVENTY-EIGHT ENGRAVINGS. 



PHILADELPHIA : 
HENRY CAREY BAIRD & CO., 

INDUSTRIAL PUBLISHERS, BOOKSELLERS AND IMPORTER 

8io Walnut Street. 

LONDON : 

E. & F. N. SPON, Ltd., 

125 STRAND. 

iSgg. 






27863 



CuPYRIGHT, 1899, 
BY 

EDWARD KIRK, 
TWO OOPIfea HtsueiVBO, 



i MAR 18 1899 )! 

Printed bv the 

WICKERSHAM PRINTING COMPANY, 

53 and 55 North Queen Street, 

Lancaster, Pa., U. S. A. 



99 



/-^9 






i 



PREFACE. 



Although it is now more than twenty years since the pub- 
lication of the author's volume, " The Founding of Metals," 
that book is still in demand. The reception which has been 
tendered to it, together with the urgent requests of many 
foundrymen for a more modern work on cupolas, has encour- 
aged .him to prepare the treatise now offered to the public. 

This volume is designed to supply a want long felt, for a 
work on melting that would give practical details regarding 
the construction and management of cupolas, and the melting 
of iron for foundry work. Several valuable books have been 
written on the moulding and founding of iron and steel, but in 
these books, as in the foundry, but comparatively little attention 
is given to the cupola ; and foundrymen and melters have been 
left to grope very much in the dark, and to rely solely on their 
own experience, in the construction and management of their 
cupolas. 

This condition of things, and the great importance of the 
subject, have combined to induce the author in the present 
work to endeavor to develop the most vital principles con- 
nected with the cupola, its construction and its use, together 
with the best practice of this country. In order to accomplish 
these ends, he has supplemented his almost lifelong experience 
by consulting the latest works on foundry practice, and by 
visiting leading and thoroughly up-to-date foundries in different 
parts of the United States. He therefore trusts that this book 
will prove to be a useful aid to foundrymen, whether owners or 
workers, both here and abroad. 

( iii ) 



IV PREFACE. 

As is the general custom of the publishers, they have caused 
the work to be supplied with a copious table of contents, as 
well as a very full index, which will render reference to any 
subject in it both prompt and easy. 

EDWARD KIRK. 

Philadelphia, February 22, i8gg. 



CONTENTS. 



CHAPTER I. 

The Cupola Furnace. 

PAGE 

Advantages of the cupola furnace for foundry work; Quantity of fuel 
required for melting iron in various kinds of furnaces; Attempts to 
decrease the amount of fuel consumed in the cupola by utilizing the 
waste heat 1 

Description of the cupola furnace; Forms of cupolas; Sizes of cupolas; 
Foundation of a large cupola ......... 2 

Advantage of iron supports over brick-work; Height of the bottom of 
the cupola; Pit beneath the cupola 3 

Bottom plate; Bottom doors; Support of the doors; Various devices for 
holding the doors in place; Construction of the casings ... 4 

Stack casing; Construction of the stack; Tuyere holes .... 5 

Location of the charging door and its construction; Lining of the casing 
and materials used for it .......'. 6 

The scaffold and its location; Construction of the scaffold; Size of the 
scaflFold i 

CHAPTER II. 

Constructing a Cupola. 

Proper location of a cupola; The scaflFold . ...... 8 

Conveyance of coal or coke to the scaflfold; Cupola foundation and its 
construction 9 

Prevention of uneven settling; Brick walls for the support of a cupola; 
Best supports for a cupola . 10 

Height of cupola bottom; Provision for the removal of the dump; Bot- 
tom doors 11 

Casing; Material for the casing or shell of the modern cupola and stack; 
Strain upon the casing due to expansion and shrinkage and its pre- 
vention; Contraction of the stack; Prevention of sparks . . .12 

What constitutes the height of cupola; Utilization of the waste heat; 
Table giving the approximate height and size of door for cupolas of 
diflferent diameters ........... 13 

Melting capacity of a cupola; Charging door; Air chamber . . .14 

(v) 



vi CONTENTS, 

PAGE 

Construction of the air chamber when placed inside the casing and when 
placed upon the outside of the shell; Air capacity of the air chamber; 
Admittance of the blast to the air chamber 15 

Location and arrangement of the air chamber when the tuyeres are 
placed high; Tap-hole 16 

Arrangement when two tap-holes are required; The spout and its con- 
struction; Tapping of slag 17 

Location of the slag-holes ; Tuyeres ; Number of tuyeres for small 
cupolas ............. 18 

Best shape of tuyere for a small cupola; Number of tuyeres for large 
cupolas ; Size of combined tuyere area ; Tuyere boxes or casings ; 
Height at which tuyeres are placed in cupolas ..... 19 

Objection to high tuyeres; Two or more rows of tuyeres; Arrangement 
of a large number of rows 20 

Area of the rows; Increase in the melting capacity with two or three 
rows of tuyeres; Lining; Material for lining the casing . . .21 

Grouting or mortar for laying up a lining; Manner of laying the brick; 
Thickness of cupola linings; Stack lining ...... 22 

Arrangement of brackets 23 

Preference by many of angle iron to brackets; Mode of putting in angle 
iron; Reduction of the lining by burning out 24 

Settling of the lining; Mode of reducing the size and weight of the bot- 
tom doors and preventing the casing from rusting off at the bottom; 
Prevention of the absorption of moisture into the lining . . .25 

Illustration of the triangular-shaped tuyere in position in the lining; 
Form of bottom plates. Fire-proof scaffolds; Exposure of the scaf- 
fold and its supports to fire 26 

Devices to make scaffolds fire-proof; Novel plan of construction of a 
scaffold and cupola house in Detroit, Mich 27 

Best and safest scaff'olds; Cupola scaffold in the foundry of Gould & 
Eberhardt, Newark, N. J., and of the Straight Line Engine Co., Syra- 
cuse, N. Y 28 

CHAPTER III. 

Cupola Tuyeres. 
Modes of supplying the cupola furnace with air; Admission of the air 
through tuyeres or tuyere holes; Former and present melting capacity 

of a cupola; Epidemics of tuyere invention 30 

The round tuyere; Arrangement of round tuyeres in the old-fashioned 

cast-iron stave cupolas 31 

Oval tuyere; Expanded tuyere 32 

Doherty tuyere 33 

Sheet blast tuyere; Horizontal slot tuyere; Mackenzie tuyere. . . 34 
Blakeney tuyere 35 



CONTENTS. Vii 

PAGE 

Horizontal and vertical slot tuyere 36 

Reversed T tuyere or vertical and horizontal slot tuyere; Vertical slot 

tuyere; Truesdale reducing tuyere . ....... 37 

Lawrence reducing tuyere .......... 38 

Triangular tuyere; Results in melting with this tuyere obtained by the 

Magee Furnace Co., Boston, Mass 39 

Water tuyere 40 

Colliau tuyere; Whiting tuyere 41 

Chenney tuyeres; The double tuyere; Mode of placing the tuyeres in 

Ireland's cupola; Claims for the double tuyere 42 

Consumption of fuel in a double tuyere cupola; Three rows of tuyeres; 

Cupola constructed by Abendroth Bros., Port Chester, N. Y. . .43 
Object in placing tuyeres in a cupola; Production of heat by consuming 

the escaping gases from the combustion of fuel . . . . .44 

Greiner tuyere; Adjustable tuyeres 45 

Cupola of the Pennsylvania Diamond Drill and Manufacturing Co., 

Birdsboro, Pa.; Bottom tuyere ........ 46 

Mode of covering the mouth of a bottom tuyere 47 

Bottom tuyere patented in this country by B. H. Hibler; Thomas D. 

West on the bottom tuyere 48 

Size of tuyeres; Size of the combined tuyere area of a cupola . . .49 
Height of tuyere; Great difference of opinion on this subject; Experi- 
ments with tuyeres at various distances above the sand bottom . . 50 
Experiment to soften hard iron by bringing the molten metal in contact 

with charcoal in the bottom of a cupola; Reason given in favor of high 

tuyeres ............. 51 

Tuyeres in stove foundry cupolas; Location of tuyeres in smaller cupolas. 52 
Tuyeres in machine and jobbing foundry cupolas, and in cupolas for 

heavy work ............ 53 

Number of tuyeres; Objection to the use of only one tuyere; Two tuyeres 

sufficient for the largest cupola in use 54 

Arrangement of a double row of tuyeres; Shape of tuyeres; Tuyeres to 

improve the quality of iron 55 

Tuyere boxes 56 



CHAPTER IV. 

Cupola Management. 

Necessity of learning the peculiarities in the working of a cupola; A 
cupola cannot be run by any given rule or set of rules; Drying the 
lining 58 

Drying a backing or filling between the casing and lining; Putting up 
the doors; Devices for raising the doors into place . . . .59 

Support of double doors; Sizes of props to support the bottom . . 60 



Vlll CONTENTS. 



Ring attachment to the prop; Superstition of older melters regarding 

the prop; Dropping the doors; Modes of releasing the prop . . 61 
Sand bottom; Sand employed for this purpose; Objection to clay sands 
and other sands; Sand which makes the very best kind of bottom . 62 

63 
64 
65 



Wetting the bottom sand; Bringing the sand into the cupola . 

Cause of leakage in the sand bottom ....... 

Boiling of iron due to a wet bottom; Pitch or slope of the bottom . 

Effect of a high pitch; Change in the action of the iron at the spout by 
the pitch of the bottom; How the bottom should be made . . .66 

Slope of the bottom in cupolas with two tap holes; Spout; Spout lining 
material 67 

Effect of the use of too much clay or of too much sand in the lining; 
Mode of making up the spout lining ....... 68 

Building up the sides of the lining; Place of the greatest strain upon the 
spout lining 69 

Proper shape of the spout lining; Cause of pools of iron forming in the 
spout; Removal of slag from the spout ....... 70 

Front; Material used for putting in the front; Mode of putting in the 
front 71 

Eflfect of working the front material too wet; Troubles due to poor front 
material 72 

Sizes of tap hole; Locating the holes . ....... 73 

Slag hole 74 

Slag hole front; Chilling of slag in the tap hole 75 

Lighting up; Mode of placing the wood and shavings in the cupola; 
Patting in the bed fuel 76 

Effect of carelessness in arranging the wood and lighting up . . .77 

The bed; The melting point in a cupola; The melting zone and deter- 
mination of its exact location; Necessity of discovering the melting 
point in order to do good melting 77 

To find the melting point 78 

Cause of trouble in melting after a cupola has been newly lined; Fuel 
required for a bed in cupolas of different diameters . . . .79 

Charging; Old way of loading or putting the fuel and iron into a cupola; 
Modern way of stocking a cupola; Correct theory of melting iron in a 
cupola 80 

Practical working of a cupola upon this theory ; Effect of too heavy 
charges of iron, and of too heavy charges of fuel; Variation in the 
■weight of the first charge of iron 81 

Variations in the per cent, of iron to fuel; Placing the charges . . 82 

Mode of placing the pieces of pig or other iron ; Distribution of the 
charge of fuel; Charging additional iron ...... 83 

Poor melting njay be due to bad charging; Improper and proper charg- 
ing of a cupola; Charging flux; On what the quantity of flux depends 84 

Blast; The old and the modern ways of giving blast to the cupola; Blast 
phenomena 85 



CONTENTS. IX 

PAGE 

Melting; When melting begins in a cupola; Difference in opinion as to 
the time for charging the iron before the blast is put on . , .86 

Best time for putting on the blast; Chilling and hardening of the first 
iron; Running of a heat without stopping in; Mode of reducing the 
size of the tap-hole 87 

No advantage in holding molten iron in a cupola to keep it hot; Proper 
management of hand-ladle work; Indication of how the cupola is 
melting by the flow of iron from the tap-hole . . . . .88 

Poking the tuyeres 89 

Fuel; Amount of fuel required in theory and in practice; Necessity of 
keeping an accurate account of the amount of iron melted . . .90 

Chief object of melting iron in a cupola; The old story of " not enough 
blast;" Necessity of an even volume of blast. ..... 91 

Tapping bars; Shapes and sizes of tapping bars 92 

Steel bar for cutting away the bod before tapping; Bod sticks; Combin- 
ation stick 93 

Objection to the combination stick; Number of bod sticks for each 
cupola; Bod material; Importance of the material of which the bod is 
composed ............. 94 

Mixture for a good bod; Bod for small cupolas; Qualities of a good bod. 95 

Tapping and stopping in; Mode of making the bod; How to make the 
tap 96 

Mode of stopping in; Difficulties in stopping in; Devices to assist in 
stopping in ............ 97 

The skill of the melter seen at the tap-hole; Uneven melting is the fault 
of the melter; Dumping .......... 98 

Removal of the small props; Bridging over of small cupolas above the 
tuyeres and mode of removing the bridge ...... 99 

Various methods of handlin_^ the dump; Removing the dump and vari- 
ous devices for this purpose 100 

Breaking up the dump and picking it over; Different ways of recovering 
the iron from the dump; Chipping out 101 

Theory of some melters to prevent iron from running into the tuyeres; 
Objection to this theory; Cupola picks ....... 102 

Daubing; Materials used 103 

Soaking fire clay; Amount of sand required for mixing with the clay; 
No advantage in using a poor cheap daubing 104 

Putting on the daubing; Shaping the lining; Object of applying daub- 
ing to a lining; Mode of making new linings 105 

Chipping off cinder and slag that adhere to the lining over the tuyeres; 
Not necessary or advisable to fill in the lining at the melting zone; 
Objections to sudden offsets or projections ...... 106 

Thickness of the daubing; Sectional view of a cupola, illustrating effect 
of excessive daubing . . . . . . . . . .107 

Shaping the lining of the boshed cupola; Special directions required for 



X CONTENTS. 

PAGE 

shaping and keeping up the lining of the patent and odd-shaped 
cupolas ............. 109 

Relining and repairing; Thickness of the lining; Location of the great- 
est-wear on the lining; Destruction of the lining at and below the tuy- 
eres; Length of time a cupola lining will last; Burning away of the 
lining 110 

Thickness of lining required to protect the casing; Repairing the lining 
at the melting zone . . . . . . . . . . .111 

Repairing a lining with split brick; Mode of making a split brick . . 112 

CHAPTER V. 
Experiments in Melting. 

Various opinions formerly held by foundrymen as to the point in a 
cupola at which the melting of iron actually took place; Different ways 
of charging or loading a cupola ........ 113 

Experiments to learn definitely at what point iron is really melted in a 
cupola; Construction of an experimental cupola ..... 114 

Results of the first experiment ......... 115 

Arrangement of the bars of iron for the next experiment . . . 116 

What was learned from this experiment; Arrangement of the bars and 
cupola for the next heat . . . . . . . . . .117 

High pressure of blast may be almost wholly due to the size of the tuy- 
eres; Arrangement of the bars for the next heat and the result of this 
experiment . . . . . . . . . . . .118 

Arrangement of the cupola for the next heat and result of the experi- 
ment 119 

Fuel used in the experiment; Reasons why iron is not melted in a cupola 

by the blast and flame of the fuel; Melting zone in a cupola . . 120 
Fire under the tuyeres .......... 121 

Low tuyeres; Results of an experiment with low tuyeres. . . . 122 

Melting zone; What determines the location of a melting zone in a 

cupola; Lowering and raising the melting zone 123 

Change in the location and depth of the melting zone .... 124 
Experiments to learn the depth of the melting zone in practical melting. 125 

Charges used in the experiments .126 

Charges with which the most melting was done in these experiments; 
Necessity of passing the blast through a certain amount of heated fuel 
before a melting zone was formed in a cupola ..... 127 
Cause of iron melted high in a cupola being made dull .... 128 
Development of the melting zone above the tuyeres; Experiments with 

a cupola with the tuyeres placed near the top; Failure of this plan . 129 
Melting with coal; Softening hard iron; Experiments in softening iron 
by passing it in molten state through charcoal in its descent from the 
melting zone to the bottom of the cupola 130 



CONTENTS. XI 

PAGE 

Time for charging; DiflFerence of opinion among foundrymen as to the 
proper time for charging; Experiments to ascertain the proper time 
for charging and putting on the blast after charging .... 132 

Devices for raising the bottom doors ........ 133 

Device for raising heavy doors 134 

CHAPTER VI. 

Fluxing of Iron in Cupolas. 

Definition of a flux; Use of fluxes; Materials used as fluxes; Purpose of 
the use of limestone in the production of pig-iron .... 135 

On what the making of a brittle cinder in a cupola by the use of lime- 
stone depends; Limestone in large quantities ..... 136 

Variation in the quantity of limestone required to produce a fluid slag; 
Weight of slag drawn from a cupola ....... 137 

Constituents of the slag; Efi'ect of flux upon iron ..... 138 

The action of fluxes on lining ......... 139 

How to slag a cupola; Cause of trouble in slagging; General method 
of charging the limestone; The slag hole ...... 140 

Slag in the bottom of a cupola; Importance of the time for drawing the 
slag; Does it pay to slag a cupola? Estimate of the cost of slagging . 141 

Shells; Use of oyster, clam and other shells; Cause of the crackling noise 
of shells when the heat first strikes them; Marble spalls . . . 142 

Experiments with mineral and chemical materials with the view of 
making a cheap malleable iron; Reasons why iron is often ruined as 
a foundry iron by improper melting and fluxing; Increase in the per 
cent, of iron lost in melting by improper melting and fluxing . . 143 

Effect of silicon on iron; Per cent, of silicon an iron may contain; Use 
at the present time of high silicon cheap southern iron . . . 144 

Heavy breakage due to the use of high silicon irons; Effect of carbon 
upon cast iron ; Removal of free carbon from iron .... 145 

Fluor spar, and its use as a flux ......... 146 

Cleaning iron by boiling; Poling molten iron ...... 147 

CHAPTER VII. 
Different Styles of Cupolas. 
Old Style Cupolas. 
Old style cupola in general use throughout this country many years ago, 

described and illustrated 149 

Practice of casting with the use of the old-style cupola .... 151 
The reservoir cupola, described and illustrated ..... 152 
Stationary bottom cupola; Old style English cupola, described and illus- 
trated 154 

Expanding cupola, described and illustrated 155 



xii CONTENTS. 

PAGE 

Ireland's cupola, described and illustrated 157 

Ireland's center blast cupola, described and illustrated .... 159 

Voisin's cupola, described and illustrated ....... 161 

Woodward's steam-jet cupola, described and illustrated .... 163 

Objection to this style of cupola; Tank or reservoir cupola, described 

and illustrated . ........... 167 

Production of Soft iron by putting a quantity of charcoal on the sand 

bottom; Use of tanks in England 169 

Mackenzie cupola, described and illustrated 170 

Management of the Mackenzie cupola ....... 172 

The Herbertz cupola, described and illustrated; Movable hearth of this 

cupola ............. 173 

Advantages of the application of a steam jet to create draft in the 

cupola . . . . . . . . . . . • .175 

Test heats with the Herbertz cupola 176 

Composition of the escaping gases from the Herbertz cupola . . . 177 
Explanation why less carbon and silica are eliminated from the iron in 

the Herbertz cupola than in the ordinary blown cupola . . . 178 
Working of the Herbertz cupola at Elizabethport, N. J .... 179 

The hearth in the cupola used at Elizabethport 180 

Process of melting; Results of test-heats at Elizabethport . . . 181 
Herbertz's cupola used for melting steel, described and illustrated; 

Melting bronze. ........... 182 

Pevie cupola, described and illustrated 184 

Object of Mr. Pevie in constructing a cupola; Stewart's cupola, described 

and illustrated ............ 186 

Rapid melting of this cupola; The Greiner patent economical cupola, 

described and illustrated .......... 188 

What the novelty of this invention consists of 189 

Principle of the workings of the Greiner cupola illustrated . . . 190 
Mr. Greiner's conclusions. ......... 191 

Points in favor of the Greiner cupola; Colliau patent hot-blast cupola, 

described and illustrated 192 

History and description of the cupola aud results obtained in melting . 193 

Claims made for the Colliau furnace 194 

The Whiting cupola, described and illustrated. 196 

Jumbo cupola, described and illustrated 198 

Charge table for the Jumbo cupola 200 

The Crandall improved cupola with Johnson patent center blast tuyere, 

described and illustrated. 202 

Mode of applying the air to this cupola 203 

Claims made for the Crandall cupola; Blakeney cupola, described and 

illustrated 204 

Advantages of this cupola 20? 



CONTENTS. XI 11 

CHAPTER VIII. 
Art in Mei<ting. 

PAGE 

The art of melting iron in a cupola but little understood by many 
foundrymen and foundry foremen; Troubles experienced in melting. 206 

No chance work in nature or in art; Necessity of understading the con- 
struction and mode of operation of a cupola to do good melting . . 207 

Location and arrangement of the tuyeres; Preparation of the cupola for 
a heat; Lighting up 208 

Melting iron in a cupola a simple process; Things to be learned and 
practiced; Necessity of a close study of all the materials used in melt- 
ing 209 

What should be the aim of every moulder; Advisability of the foreman 
of a foundry being the melter; Duties of the melter .... 210 

CHAPTER IX. 

SCAI.KS AND THEIR USE. 

Necessity of an accurate scale upon the scaffold; Size of scale required; 
What the melting of iron in a cupola, when reduced to an art, consists 
in 211 

Division of the fuel and iron into charges; The theory of melting not 
understood by many foundrymen; Incorrect methods of calculating 
the charges of iron and fuel . . 212 

Use of old, worn-out scales condemned 213 

CHAPTER X. 

The CUPOI.A Accounts. 

Value of cupola records; Manner of keeping the accounts . . . 214 

Cupola report of Abendroth Bros., Port Chester, N. Y 215 

Cupola report of Byram & Co., Iron Works, Detroit, Mich. . . . 216 

Daily report of Foundry Department, Lebanon Stove Works . . . 217 

Melting sheet of Syracuse Stove Works 218 

Report of castings in Shop 219 

Cupola slate for charging and cupola report 220 

Blanks for reports and records and mode of making them out; Report 

on a slate; Correctness essential to the value of a cupola account . 221 

CHAPTER XL 

Pig Mould for Over Iron. 
Saving in iron and labor by the use of cast iron pig moulds for collecting 
over iron 222 



XIV CONTENTS. 

CHAPTER XII. 
What a Cupoi,a wii,i. Melt. 

PAGE 

Chief use of the cupola furnace; Employment of the cupola furnace for 
other purposes than melting iron 223 

Quantity of iron that can be melted in a cupola; Number of hours a 
cupola may be run; Size and weight of a piece of cast-iron that can be 
melted in a cupola; Charging large pieces of iron at the foundry of 
Pratt & Whitney Co., Hartford, Conn.; Melting of cannon and other 
heavy government scrap at the Eobdell Car Wheel Co., Wilmington, 
Del 224 

CHAPTER XIII. 

Melting Tin Plate Scrap in a Cupola. 

Various ways of preparing the scrap for charging; Attempts to recover 
the tin deposited upon the iron; Quality of the molten metal from the 
scrap 225 

Susceptibility of the molten metal to the effect of moisture; Uses of the 
metal; Production of a gray metal from the scrap; Tests to learn the 
amount of metal lost in melting the scrap . ..... 226 

Action of tin as a flux when melted with iron; Uusuitability of galvan- 
ized sheet-iron scrap for melting in a cupola; Doctoring the metal 
from tin-plate-scrap; Process of melting tin- plate-scrap . . . 227 

Fluxing tin-plate-scrap; Construction of a cupola expressly for melting 
tin-plate-scrap ..... . . .... 228 

Cost of melting tin-plate-scrap and profit in the business. . . . 229 

CHAPTER XIV. 

Cost of Melting. 

Unreliability of melting accounts as generally kept; Objection to measur- 
ing fuel in baskets . . . . . . . . . . . 230 

Results of an accurate account of the melting in a foundry in New Jer- 
sey; Cupola book; Proper method of figuring the cost of melting per 
ton 231 

CHAPTER XV. 

Examples of Bad Melting. 
Necessity of giving causes of poor melting; Trouble with the cupolas at 

the stove foundry of Perry & Co., Sing Sing, N. Y 233 

Cause of the trouble; Sectional views of lining out of shape . . . 236 

Remedy of the troubles 240 

Bad melting at a West Troy Stove Works; Visit at the foundry of Daniel 
E. Paris & Co., West Troy, N. Y.; Inspection of the foundry with a 
view of locating the trouble . ........ 242 



CONTENTS. XV 

PAGE 

Trouble due to the use of too much fuel 243 

Experimeut of running the cupola with less fuel ; Objection of the 

tnelter to the experiment ......... 244 

Result of the experiment; Heats with a still further reduction of fuel . 246 
Cause of bad melting in this foundry ....... 247 

Warming up a cupola; Visit to the plant of the Providence Locomotive 

Works; Trouble with the cupola .... .... 248 

Cause of the poor melting due to the bed being burned too much . . 249 
Remedy of the trouble; Bad melting, caused by wood and coal; Cause 

of poor melting in one of the leading novelty foundries in Philadelphia 250 
Poor melting in a Cincinnati cupola; Sectional elevation showing the 

condition of the cupola 251 

Uneven burning of the bed ; Reason for the necessity of dumping a 

cupola at the foundry of Perry & Co. ....... 253 



CHAPTER XVI. 

MEI.TERS. 

Respect due to the practical and scientific tnelter; Unfortunate position 
of a poor melter; Interference with a good melter frequently the cause 
of poor melting 254 

Necessity of furnishing proper tools for chipping out, and making up 
the cupola; What should be the aim of every melter .... 255 

Interest of every foundryman to keep his melter posted .... 256 



CHAPTER XVII. 

Expi<osioN OF Molten Iron. 

Conditions under which molten iron is explosive; Explosions caused by 
a wet spout or a wet bod 257 

Cause of sparks; Various causes of the explosion of molten iron; Explo- 
sion due to thrusting a piece of cold, wet or rusted iron into molten 
iron 258 

Explosion of molten iron when poured into a damp or rusted chill- 
mould or a wet sand-mould; Accident in the foundry of Wm. McGil- 
very & Co., Sharon, Pa 259 

Explosion of molten iron when poured into mud or brought into contact 
with wet rusted scrap; Accident in the foundry of James Marsh, Lewis- 
burg, Pa.; Accident at the foundry of North Bros., Philadelphia, Pa. 260 

Explosion at the foundry of the Skinner Engine Co., Erie, Pa., and at 
the foundry of the Buffalo School Furniture Co., Buffalo, N. Y. . . 261 

Prevention of explosions 262 



XVI CONTENTS. 

CHAPTER XVIII. 
Spark-Catching Devices for Cupolas. 

PAGE 

Spark-catcher in old-style cupolas 263 

Spark-catching device for modern cupolas 264 

Return flue cupola spark-catcher, designed by John O. Keefe. . . 266 

Other spark-catching devices 268 

The best spark-catching device; Cause of sparks being thrown from a 
cupola; Prevention of sparks being carried out of the stack; Enlarged 
stack 269 

CHAPTER XIX. 

Hot Blast Cupolas. 
Hot blast cupolas constructed by Jagger, Treadwell & Perry . . . 271 
Cupola at the foundry of Ransom & Co., Albany, N. Y.; Arrangement 

with exhaust pipes ........... 273 

Heating the blast for a cupola; Waste heat from a cupola; Plans for 

utilizing the heat escaping from a cupola ...... 274 

Cupolas at the Carnegie Steel Works, Homestead, Pa.; Prevention of 

the escape of heat in low cupolas 275 

CHAPTER XX. 

Taking off the Blast During a Heat — Banking a Cupola— Blast 
Pipes, Blast Gates. 

Explosions in blast pipes, blast gauges, blast in melting; Length of time 
the blast can be taken off a cupola; Management of a cupola from 
which the blast is taken off ........ . 276 

Banking a cupola; Communication from Mr. Knoeppel, Foundry Super- 
intendent, Bufi'alo Forge Co., Buffalo, N. Y., on banking a cupola . 277 

Blast pipes; Importance of the construction and arrangement of blast 
pipes; Underground blast pipes ........ 279 

Objection to underground blast-pipes; Materials used in the construction 
of blast-pipes; Galvanized iron pipes 280 

Table prepared by the Buff"alo Forge Co , Buffalo, N. Y., as a guide for 
increasing the diameter of pipes in proportion to the length; Diameter 
of blast-pipes; Friction in pipes ........ 281 

Frequent cause of a blower being condemned as being insufficient. . 282 

Table showing the necessary increase in diameter for the diff"erent 
lengths 283 

Connection of blast pipes with cupola ; Combined area of the branch 
pipes 284 

Table of diameter and area of pipes 285 

Connecting blast pipes direct with tuyeres ; Perfect connection of air 
chambers; Poor arrangement of pipes in a "perfect cupola" . . 286 



CONTENTS. xvii 

PAGE 

Mode of connecting a belt-air chamber with the tuyeres; Best way of 
connecting blast pipes with cupola tuyeres . . . . . . 288 

Blower placed near cupola .......... 289 

Poor melting often caused by long blast pipes; Perfect manner of con- 
necting the main pipe with an air chamber; Blast gates; Advantage of 
the employment of the blast gate ........ 290 

Explosions in blast pipes; Prevention of such explosions; Blast gauges; 
Variety of gauges 292 

What an air-gauge to be of any value in melting must indicate . . 293 

Blast in melting; Means for supplying the required amount of air to the 
cupola; Machines for supplying the blast; Relative merits of a posi- 
tive and non-positive blast ......... 294 

Amount of air required for combustion of the fuel in melting a ton of 
iron 295 

Theory of melting in the old cupolas with small tuyeres; Necessity of 
discarding the small tuyeres ......... 296 

Points to be remembered in placing tuyeres in a cupola; Best tuyere for 
large cupolas; Size of the largest cupolas in which air can be forced to 
the center from side tuyeres ......... 297 

Cupolas of the Carnegie Steel Works, Homestead, Pa. ; Experiments 
with a center blast tuyere 298 

Claims for the center blast 299 

CHAPTER XXI. 

Blowers. 
Placing a blower; Convenient way of placing a blower near a cupola . 30(1 
Fan blowers: Buffalo steel pressure blower; Claims for this blower . 301 
Blower on adjustable bed, and on bed combined with countershaft . 303 
Blower on adjustable bed, combined with double upright engine . . 305 
Buffalo electric blower built in "B" and steel pressure types . . . 306 
Buffalo blower for cupola furnaces in iron foundries .... 308 
Table of speeds and capacities as applied to cupolas; Smith's Dixie fan 

blower 309 

Forced blast pressure blowers; The Mackenzie blower .... 311 

Description of and claim for this blower . . . . . . .312 

Sizes of the Mackenzie blower; Construction and operation of the ma- 
chine 313 

Directions for setting up blower; The Green patented positive pressure 

blower; Claims for this blower . . 314 

Complete impeller, Illustrated and described; Directions for setting up 

blower 316 

Efificiency of blower 317 

Power; Rule for estimating the approximate amount of power required 
to displace a given amount of air at a given pressure .... 318 



xviii CONTENTS. • 

TAOE 

Staudard foundry blowers driven by steam, dimensions in inches . . 319 

Speed of foundry blowers 320 

Connersville cycloidal blower . ... . . . . • 321 

Special value of combining the epi- and hypo-cycloids to form the con- 
tact surfaces of impellers. ......... 322 

Advantages claimed for the Connersville cycloidal blower . . . 823 
Table of numbers, capacities, etc., of the cycloidal blowers; What is 
meant by ordinary speed; Vertical blower and engine on same bed 

plate 326 

Blower and electric motor 327 

Garden City positive blast blowers 328 

Root's rotary positive pressure blower ....... 329 

Claims for this blower 330 

CHAPTER XXII. 

Cupolas and Cupola Practice up to Date. 

Kinds of furnaces employed in the melting of iron for foundry work; 
Coke the almost universal fuel for foundry work; Quantity of fuel 
required in the different kinds of furnaces ...... 332 

Rule for charging a cupola; Height or distance the tuyeres should be 
placed above the sand bottom 333 

Function of the fuel placed below the tuyeres; Fallacy of the claim that 
it is necessary to have tuyeres placed high to collect and keep iron 
hot for a large casting; Objection to low charging doors . . . 334 

Highest cupolas in use in this country; What is required for a cupola to 
do economical melting; Determination of the top of the melting zone. 335 

Tests to ascertain the amount of fuel required in the charges and the 
amount of iron that can be melted upon each charge; General con- 
sumption of too great an amount of fuel ...... 336 

On what the per cent, of fuel required in melting depends; Necessity of 
reducing the melting to a system; Advisability of keeping an accurate 
cupola record ...... ...... 337 

CHAPTER XXIII. 

Cupola Scraps. 
Brief paragraphs illustrating important principles; Terms used in diflfer- 

ent sections of the country to indicate the melting of iron in a cupola. 339 
Best practical results for melting for general foundry work . . . 343 
Remarks by Mr. C. A. Treat; Difficulty experienced by a foundryman 

in obtaining reliable cupola reports for publication .... 344 

NOTE. 

Paxson-CoUiau Cupola 345 

Index 347 



CHAPTER I. 

THE CUPOLA FURNACE. 

The cupola furnace has many advantages over any other 
kind of furnace for foundry work. 

It melts iron with less fuel and more cheaply than any other 
furnace, can be run intermittently without any great damage 
from expansion and contraction in heating and cooling. Large 
or small quantities of iron may be melted in the same furnace 
with very little difTerence in the per cent, of fuel consumed, and 
the furnace can readily be put in and out of blast. Conse- 
quently in all cases where the strength of the metal is not of 
primary importance, the cupola is to be preferred for foundry 
work. 

In the reverberatory furnace from ten to twenty cwt. of fuel 
is required to melt one ton of iron. 

In the pot furnace one ton of coke is consumed in melting a 
ton of cast iron, and two and a half tons in melting a ton of 
steel. 

In the blast furnace twenty to twenty-five cwt. of coke is con- 
sumed in the production of a ton of pig iron. 

In the cupola furnace a ton of iron is melted with from 172 
to 224 lbs. of coke. 

It will thus be seen that in the cupola furnace we have the 
minimum consumption of fuel in melting a ton of iron, although 
the amount consumed is still three or four times that theoret- 
ically required to do the work. 

Many attempts have been made to decrease even this small 
amount of fuel consumed in the cupola, by utilizing the 
waste heat passing off from the top for heating the blast. But 

(I) 



2 THE CUPOLA FURNACE. 

the cupola being only intermittently at work has rendered all 
such attempts futile. 

The cupola furnace is a vertical furnace consisting of a hollow 
casing or shell, lined with fire-brick or other refractory material, 
resting vertically upon a cast iron bottom plate, having an 
opening in the centre equal to the inside diameter of the lining 
and corresponding in shape to the shape of the furnace. This 
opening is closed with iron doors covered with sand when the 
furnace is in blast. Two or more openings are provided near 
the bottom of the furnace for the admission of air by draught 
or forced blast. A small opening, on a level with the bottom 
plate, is arranged for drawing ofif the molten metal from the 
furnace. An opening, known as the charging door, is made in 
the side of the casing at the top of the furnace for feeding it 
with fuel and iron, and a stack or chimney is constructed 
above the charging door for carrying off the escaping smoke, 
heat and gases. 

Cupolas have been constructed cylindrical, elliptical, square 
and oblong in shape, and they have been encased in stone, 
brick, cast iron and wrought iron casings. Frora one to a 
hundred or more tuyeres have been placed in a cupola, and the 
stationary and drop bottoms have been used. At the present 
time cupolas are constructed almost entirely in a cylindrical or 
elliptical form, and the casing is made of wrought iron or steel 
boiler plate. The stack casing is made of the same material 
and is extended up to a sufficient height to give draught for 
lighting up, and to carry ofif the escaping heat and gases. The 
drop bottom has been almost universally adopted, at least in 
this country. 

Cupolas are constructed of various sizes, to suit the require- 
ments of the foundry they are to supply with molten metal. 
Those of large size are, when charged with iron and fuel, of 
immense weight, and require a very solid foundation to support 
them. The foundation is generally made of solid stone work 
up to the level of the foundry floor; upon this is placed brick 
work laid in cement, or cast iron columns or posts, for the sup- 



THE CUPOLA FURNACE. 3 

port of the iron bottom and cupola. In all cases where the 
cupola is set at sufficient height from the floor to admit of the 
use of the iron supports they are to be preferred to brick-work, 
as they admit of more freedom in removing the dump and re- 
pairing the lining. The columns or posts are placed at a suffi- 
cient distance apart to permit the drop doors to swing free 
between them. This arrangement removes the liability to 
breaking the doors by striking the cupola supports in falling, 
and admits of their being put back out of the way when remov- 
ing the dump. 

The height the bottom of the cupola is placed above the 
moulding floor depends upon the size of the ladles to be filled, 
and varies from fourteen inches to five feet. If placed too high 
for the sized ladle used, considerable iron is lost by sparks and 
drops separating from the stream in falling a long distance, and 
the stream is more difficult to catch in the ladles. For hand 
ladle work it is better to place the cupola a little higher than four- 
teen inches, and rest the ladle upon a hollow oblong pedestal 
eight or ten inches high, and open at both ends, than to set it 
upon the floor. The ladle can then be moved back or forward 
to catch the stream, and iron spilled in changing ladles falls 
inside the pedestal, and is prevented from flying when it strikes 
the hard floor, and is collected in one mass inside the pedestal. 
This arrangement reduces the liability of burning the men 
about the feet and renders it easier to lift the full ladle. 

If a cupola is set very low, it is then necessary to make an 
excavation or pit beneath it to permit of the removal of the 
dump, and repairing of the lining. This pit is made as wide as 
it conveniently can be, and of a length equal to two or three 
times the diameter of the cupola. The distance from the 
bottom plate to the bottom of the pit should not be less than 
three feet. The bottom of the pit is lined with a hard quality 
of fire-brick set on edge, and the floor sloped from the edges to 
the centre, and from the end under the cupola outward, so that 
any molten iron falling within the dump will flow from under 
the cupola, and thus facilitate its removal. In the centre of the 



4 THE CUPOLA FURNACE. 

pit under the cupola a block of stone or a heavy block of iron 
is securely placed, upon which to rest the prop for the support 
of the iron bottom doors. 

The bottom plate is made of cast iron, and must be of 
sufficient thickness and properly flanged or ribbed to prevent 
breaking. If broken when in place, it can not be removed, and 
it is then almost impossible to securely bolt it so as to hold 
it in place. The plate must be firmly placed upon the iron sup- 
ports or brick work, so that no uneven strain will be put upon 
it by the weight of the cupola and stack. 

The bottom doors are made in one piece or in two or more 
sections. For large cupolas they are generally made in two or 
four sections to facilitate raising them into place. Bottom 
doors are made of cast or wrought iron. Those made of cast 
iron are, when in place, the stifitest and firmest. Those made 
of wrought iron are the lightest and easiest to handle, but are 
also more liable to be warped by heat in the dump, and to 
spring when in place. The door, or doors, whether made of 
cast or wrought iron, have wide flanges to overlap the bottom 
plate and each other when in place, to prevent the sand, when 
dry, running out through cracks and making holes in the sand 
bottom. The doors are supported in place by a stout iron or 
wooden prop ; and when the doors are light, or sprung, one or 
more additional props are put in for safety. Numerous bolts 
and latches have been devised for holding the doors in place, 
but they have all been abandoned in favor of the prop, which 
is the safest. Sliding doors, or plates, have been arranged 
upon rollers to slide into place under the cupola from the sides, 
and be withdrawn by a ratchet or windlass to dump the cupola. 
They admit of easy manipulation ; but in case of leakage of 
molten iron through the sand bottom, they are sometimes burnt 
fast to the bottom plate and cannot be withdrawn, and for this 
reason the sliding door is seldom used. 

The casings are made of cast or wrought iron plate. When 
made of cast iron they are cast in staves, which are put in place 
on the iron bottom and bound together by wrought iron bands ; 



THE CUPOLA FURNACE. 5 

these bands being shrunk on. Or they are cast in cyHndrical 
sections, which are placed one on top of another, and bolted 
together by the flanges. This kind of casing generally cracks 
from expansion and shrinkage in a short time, and is the poor- 
est kind of casing. With the cast iron casing a brick stack, 
constructed upon a cast iron plate supported by four iron col- 
umns, is generally used. The wrought iron casing is more 
generally employed at the present time than that of cast iron. 
It is made of boiler plate, securely riveted together with one 
or two rows of rivets ; but one row of rivets, and those three 
inches apart, is generally found to be sufificient, as the strain 
upon the casing, when properly lined, is not very great. 

The stack casing is generally made of the same material as 
that of the cupola, and is a continuation of the cupola casing; 
the two generally being made in one piece. 

The stack is made the same size as the cupola, or is con- 
tracted or enlarged according to the requirements or fancy of 
the foundryman. A contracted stack gives a good draught, 
but throws out a great many sparks at the top. An enlarged 
stack gives a poor draught, unless it is very high, but throws 
out very few sparks at the top. As sparks are very objection- 
able in some localities, and not in others, different sized stacks 
are used. When surrounded by high buildings or hills, the 
stack must be made of sufficient height to give the necessary 
draught for lighting up in all kinds of weather, and they vary 
in height from a few feet above the foundry roof to twenty or 
thirty feet. Bands of angle iron are sometimes riveted to the 
inside of the cupola and stack casing to support the lining, and 
admit of sections being taken out and replaced without remov- 
ing the entire lining. 

The casing and lining are perforated with two or more tuyere 
holes near the bottom, for the admission of air by draught or 
forced blast. These tuyeres, when supplied with a forced 
blast, are connected with the blower by branch pipes to each 
tuyere, or are supplied from an air chamber riveted to the 
cupola casing either on the outside or inside. The air chamber 



6 THE CUPOLA FURNACE. 

is made three or four times the area of the blast pipe, and is sup- 
plied from the blast pipe connecting it with the blower. An 
opening is made through the casing and lining, just above the 
bottom plate, for drawing the molten iron from the cupola, and 
a short spout is provided for running it into the ladles. An- 
other small opening is sometimes made, just under the lower 
level of the tuyeres, for tapping or drawing off the slag from 
the cupola. This opening is never used except when a large 
amount of iron is melted, and the cupola is kept in blast for a 
number of hours. 

An opening for feeding the furnace, known as the charging 
door, is placed in the cupola at a height varying from six to 
twenty feet above the bottom plate, according to the diameter 
of the cupola. This opening is sometimes provided with a 
cast iron frame or casing on the inside to protect the lining 
around the door when putting in the fuel and iron. A door 
frame is placed upon the outside, upon which are cast lugs for a 
swinging door, or grooves for a sliding door. The door for 
closing the charging aperture may consist of a cast or wrought 
iron frame filled with fire-brick, or be made of boiler plate with 
a deep flange all around for holding fire-brick or other refrac- 
tory material. The sliding door consists of an iron frame 
filled in with fire-brick, and is hung by the top, and moved up 
and down with a lever or balance weights. ■ This door is moved 
up and down in grooves cast upon the door frames, which 
grooves frequently get warped by the heat, and hold the door 
fast. The hinge or swing door, with plenty of room for expan- 
sion and shrinkage, is the door generally used. 

The casing is lined from the bottom plate to the top of the 
stack with a refractory material. A soft refractory fire-brick, 
laid up with a grout composed of fire-clay and sand, is used for 
lining in localities where such material can be obtained. In 
localities where fire-brick can not be procured, soapstone from 
quarries or the bottoms of small creeks, is laid up with a re- 
fractory clay. Some grades of sandstone or other refractory 
substances are also employed for lining. Native refractory 



THE CUPOLA FURNACE. 7 

materials are seldom homogeneous, and those which have been 
ground and moulded, or pressed into blocks, make the best lin- 
ings. The thickness of the lining varies in large and small 
cupolas. Those in the large cupolas are from six to nine 
inches, and in small cupolas from four to six inches. 

The cupola charging aperture is placed at too great a height 
from the floor to admit of the cupola being charged or loaded 
rom the floor, and a scaffold or platform is erected from which 
to charge it. The scaffold is generally placed in the rear of the 
cupola, so as to be out of the way when removing the molten 
iron in crane ladles. But for hand ladle work it is placed at 
any point most convenient for getting up the stock, and the 
charging aperture placed in the cupola at any point most con- 
venient for charging. For very large cupolas the scaffold is 
frequently constructed to extend all around the cupola, and a 
charging aperture is placed in the cupola on each side, so that 
it may be more rapidly charged. The scaffold is constructed 
of wood or iron frame work, or is supported by a brick wall. 
The floor is placed level with the bottom of the charging 
aperture, or is placed from one to two feet below it. The scaf- 
fold should be made large enough to place a weighing scale 
in front of the charging door, to hold iron and fuel for several 
heats, and have plenty of room for handling the stock when 
stocking the scaffold and charging the cupola, Nine-tenths of 
the scaffolds are too small for the work to be done on them, 
and the cupola men work to a great disadvantage when hand- 
ling the stock. Much of the bad melting done in foundries 
can be traced directly to the lack of room on the scaffold for 
properly charging the cupola. 

Having thus given a general outline description of the cupola 
furnace, we shall in the next chapter describe in detail where to 
locate a cupola and how to construct it. 



CHAPTER II. 

CONSTRUCTING A CUPOLA. 

When about to construct a cupola to melt iron for foundry 
work, the first thing to be decided on is the proper location. In 
deciding this a number of points are to be taken into consider- 
ation, the two most important of which are the getting of the 
stock to the cupola and the taking away of the molten iron. It 
should be borne in mind that there is more material to be 
taken to a cupola than is to be taken away from it. For this 
reason the cupola should be located as convenient to the stock 
as possible. It must also be borne in mind that the object in 
constructing a cupola is to obtain fluid molten iron for the work 
to be cast, and if the cupola is located at so great a distance 
from the moulding floors that the molten metal loses its fluidity 
before it can be poured into the mould, the cupola fails in the 
purpose for which it was constructed. 

If the work to be cast is heavy and the greater part of the 
molten metal is handled by traveling or swinging cranes, the 
small work may be placed near the cupola and the cupola 
located at one side or end of the foundry near the yard. But 
if the work is all light hand-ladle or small bull-ladle work, the 
cupola should be located near the centre of the moulding-room 
so that the molten iron may be rapidly conveyed to the moulds 
in all parts of the room. 

SCAFFOLD. 

It is often found difificult, owing to the shape of the mould- 
ing-room and location of the yard, to place the cupola conven- 
ient for getting the stock to it and the molten iron away from 
it. When this is the case, means must be provided for getting 

(8) 



CONSTRUCTING A CUPOLA. 9 

the stock to the cupola and the cupola located at a point from 
which the molten metal can be rapidly conveyed to the moulds. 
At the present low price of wrought iron and steel, a fire-proof 
cupola scafifold can be constructed at a very moderate cost, and 
the difficulty of locating the cupola convenient to the yard may 
be overcome by constructing a scafTold of a sufficient size to 
take the place of a yard for iron and fuel. The scafTold may 
be constructed under the foundry roof and made of proper 
size to hold one or two cars of coal or coke, a hundred tons of 
pig and scrap iron and all the necessary material for a cupola. 
The space under the scafifold can be utilized as moulding floors 
for light work or for core benches, core oven, ladle oven, sand- 
bins, etc. The cupola and its supplies are then under roof, and 
there is no trouble from cupola men staying at home in bad 
weather, as is often the case when the cupola and stock are out 
of doors. 

When this arrangement is adopted, an endless chain or 
bucket elevator should be constructed to convey the coal 
or coke to the scafTold as fast as it is shoveled from the truck 
or car. Another elevator should be provided for pig and scrap 
iron, and as the iron is thrown from the car it is broken and at 
once placed upon the scafTold convenient for melting. This 
arrangement saves considerable expense for labor in the rehand- 
ling of iron and fuel, and also prevents the loss of a large amount 
of iron and fuel annually tramped into the mud in the yard and 
lost. The saving in labor and stock in a short time will pay the 
extra expense incurred in constructing this kind of scafTold. 

CUPOLA FOUNDATION. 

Too much care cannot be taken in putting in a cupola foun- 
dation, for the weight of a cupola and stack, when lined with 
fire-brick to the top, amounts to many tons, and when loaded 
with fuel and iron for a heat to many tons more. If the foun- 
dation gives way and the cast iron cupola bottom is broken by 
uneven settling, the cupola is rendered practically worthless, for 
it is impossible to replace the bottom with a new one without 



10 THE CUPOLA FURNACE. 

taking out the entire lining, which entails much expense, and 
it is almost impossible to bolt or brace the plate so as to keep 
it in place. 

The foundation should be built of solid stone work, and if a 
good foundation cannot be had, piles must be driven. Separate 
stone piers should never be built for each column or post, for 
they frequently settle unevenly and crack the bottom plate. 
Uneven settling and breaking of the bottom are, to a large ex- 
tent, prevented by placing a heavy cast iron ring upon the 
stone work upon which to set the cupola supports. This ring 
should be placed several inches below the floor to prevent it 
being warped and broken by the heat in the dump. 

When brick walls are constructed for the support of a cupola, 
the bottom plate is made square, from two to three inches 
thick and strongly ribbed or supported by railroad iron be- 
tween the walls, to prevent breaking. The walls do not admit 
of sufficient freedom in removing the dump and for this reason 
are, at the present time, seldom used in the construction of cu- 
polas. Even when the cupola is set so low that a pit is required 
for the removal of the dump, the iron supports are used and the 
pit walls built outside of them. When the round cast iron 
columns are employed, the plate must be made square or with a 
projection for each column, to admit of the columns being 
placed at a sufficient distance apart to let the bottom doors 
swing between them. The best supports for a cupola are the 
T-shaped posts. They take up less room under the cupola and 
are less in the way when removing the dump than the round 
columns, and when slightly curved at the top, can be placed at 
a sufficient distance apart to permit of the drop doors swinging 
between them. When these posts are used, the bottom plate 
is made round and of only a slightly larger diameter than the 
cupola shell or air chamber, and when made of good iron and 
the foundation plate is used, the bottom plate does not require to 
be more than i ^ or 2 inches thick for the largest sized cupola. 
The supports when curved at the top must be bolted to the 
plate to hold them in place. 



CONSTRUCTING A CUPOLA. II 



HEIGHT OF CUPOLA BOTTOM. 



The height the bottom of a cupola or spout should be placed 
above the moulding floor or gangway, depends upon the class 
of work to be cast. For small hand-ladle work the proper 
height is 1 8 to 20 inches; for small bull- and hand-ladle work 
24 to 30 inches ; and for large crane-ladle work three to five 
feet. 

It is very difficult and dangerous to change ladles and catch 
a large stream from a high cupola in hand-ladles ; and when 
pieces are only cast occasionally, requiring the use of a large 
crane-ladle, it is better to place the cupola low and dig a pit in 
front of it, in which to set the ladle when a large one is re- 
quired for the work. 

When the cupola is set low, room must be made for the re- 
moval of the dump. This may be done by constructing a wall 
in front of the cupola to keep up the floor under the spout, and 
lowering the floor under and around the back part of the 
cupola. When the cupola is so situated that this can not be 
done, a pit should be constructed for the removal of the dump. 

BOITOM DOORS. 

For cupolas of small diameter, but one bottom drop door is 
used. But when the cupola is of large diameter the door, if 
made in one piece, would be so large that there would not be 
room for it to swing clear of the foundation without setting the 
cupola too high, and the door would be very heavy and difficult 
to raise into place. For large cupolas the door is cut in the 
middle and one-half hung to the bottom on each side. Four 
and six doors are sometimes used, but they are always in the 
way when taking out the dump, and require more care in put- 
ting in place and supporting. 

The doors are generally made of cast iron, and vary in thick- 
ness from a half-inch to an inch and a half in thickness, and are 
frequently very heavy and diflicult to raise into place. If the 
doors are large they are much lighter and easier to handle 



12 THE CUPOLA FURNACE. 

when made of wrought iron, and if properly braced answer 
the purpose equally as well as the stififer cast iron one. If the 
lugs on the bottom plate are set well back from the opening, 
and the lugs on the doors made long, the doors drop further 
away from the heat of the dump, and may be swung back and 
propped up out of the way when removing the dump. 

CASING. 

The casing or shell of the modern cupola and stack is made 
of iron or steel boiler plate, riveted together with one or two 
rows of rivets at each seam. The thickness of the plate required 
depends upon the diameter and height of the cupola and stack. 
The lining in the stack is seldom renewed, while the lining in 
the cupola is often removed every few months and replaced 
with a new one, and the casing must be of a sufhcient thickness 
to support the stack and lining when the cupola lining is re- 
moved. The strain upon the casing due to expansion and 
shrinkage is not very great when properly lined ; but when im- 
properly lined with a poor quality of fire-brick, the expansion 
may be so great as to tear apart the strongest kind of casing. 
The only way to prevent this is to take care in selecting the 
fire-brick, and in laying up the lining. The greatest wear and 
tendency to rust is in the bottom sheet, and it is also weakened 
by cutting in the front, tuyere and slag holes, and should be 
made of heavier iron than any other part of the casing. Plate 
of y^ inch or ^^ inch thickness is heavy enough for almost any 
sized cupola. The cupola and stack casing are generally made 
in one piece, the cupola ending at the charging door and the 
stack beginning at the same point. The stack may be con- 
tracted above or below the charging door, and made of smaller 
diameter than the cupola. This gives a better draught and 
requires less material for casing and lining; but it also in- 
creases the number of sparks thrown from the cupola when in 
blast. Where sparks are very objectionable, as in closely built 
up neighborhoods, it is better to make the cupola and stack of 
the same diameter, or to enlarge the stack from the bottom of 



CONSTRUCTING A CUPOLA. 1 3 

the charging door. This may be done by placing a cast iron 
ring upon the top of the cupola shell, and supporting it by 
brackets riveted to the shell, and placing the stack shell upon 
the ring. The sparks then fall back into the cupola if the stack 
is of a good height, and very few are thrown out at the top. 

The height of a cupola is the distance from the top of the 
bottom plate to the bottom of the charging aperture. Many 
plans have been devised for utilizing the waste heat from a 
cupola, but the only practical means so far discovered is to 
construct a high cupola. The heat lost in a low cupola is then 
utilized in heating the stock in the cupola before it escapes 
from it. But all the heat is not utilized in this way, for a great 
deal of gas escapes unconsumed. This is shown by the in- 
crease in flame as the stock settles in the cupola to a point at 
which the oxygen from the charging aperture combines with 
the escaping gas in sufificient quantity to ignite it, when it 
burns with a fierce flame above the stock. Still a great deal 
more heat is utilized in a high cupola than in a low one. 

It is well known among iron founders that a high cupola will 
melt more iron in a given time and with less fuel than a low one 
of the same diameter. Therefore the charging aperture should 
be placed at the highest practicable point. There is a limit to 
the height at which the aperture in a small cupola can be 
placed, for where the diameter is small the iron in settling fre- 
quently lodges against the lining and hangs up the stock. 
When this occurs the stock has to be dislodged by a long bar 
worked down through from the charging aperture. If the 
aperture is placed at too great a height and the lodgment takes 
place near the bottom, the trouble cannot be remedied with a 
bar, and melting stops. Cupolas of large diameter may be 
made of almost any height desired, but there seems to be a 
limit to the height at which heat is produced in a cupola by the 
escaping gases, and we have arranged the following table from 
practical observation, giving the approximate height and size 
of door for cupolas of different diameters : 



14 



THE CUPOLA FURNACE. 



Diameter 


Height of 


Size of Charging 


Melting Capacity 


Melting Capacity 


Inside Lining, 


Cupola, 


Door, 


per Hour, 


per Heat, 


Inches. 


Feet. 


Inches. 


Tons. 


Tons. 


i8 


6-7 


15 X 18 


y^-% 


I — 2 


20 


7-8 


18 X 20 


%-^ 


2—3 


24 


8-9 


20 X 24 


I — 2 


3—5 


30 


9 — 12 


24 X 24 


2—5 


4 — 10 


40 


12—15 


30 X 36 


4-8 


8—20 


50 


15—18 


30 X 40 


6 — 14 


15—40 


60 


16—20 


30x45 


8—16 


25 — 60 



The melting capacity of a cupola varies with the kind of fuel 
used. One-fourth more iron can be melted per hour with coke 
than with coal, and the melting capacity per heat is greatly in- 
creased by the tapping of slag and number of tuyeres. 



CHARGING DOOR. 

The charging door may be made in one or two sections and 
lined with fire-brick or daubed with fire-clay; or it may be 
made of wire gauze placed in an iron frame. The charging 
door is of but little importance in melting, as it is seldom 
closed during the greater part of the heat, and is only of service 
to give draught to the cupola when lighting up, and to prevent 
sparks being thrown upon the scaffold during the latter part of 
the heat. 

AIR CHAMBER. 

The air chamber for supplying the tuyeres with blast may be 
constructed either outside or inside the cupola shell. When 
placed inside, the cupola must be boshed and the lining con- 
tracted at the bottom to make room for the chamber without 
enlarging the diameter of the cupola casing. When the cupola 
is large this can readily be done, and the boshing of the cupola 
increases its melting capacity; but small cupolas cannot be 
contracted at the bottom to a sufificient extent to admit of an 
air chamber being placed inside without interfering with the 
dumping of the cupola. When placed inside, the chamber may 
be formed with cast iron staves made to rest upon the bottom 
plate at one end and against the casing at the other. The 



CONSTRUCTING A CUPOLA. 1 5 

staves are flanged to overlap each other with a putty joint, and 
when new make a very nice air chamber. But when the Hning 
becomes thin they become heated and frequently warp or 
break, and permit the blast to escape through the lining to so 
great an extent that the lining has to be removed and the 
staves replaced with new ones. 

The air chamber, when constructed inside the casing, should 
be made of boiler plate, and securely riveted to the casing to 
hold it in place and prevent leakage of blast through the lining. 
It must be constructed of a form to correspond with the bosh- 
ing of the cupola, and of a size to supply a sufficient quantity 
of blast to all the tuyeres. If these conditions cannot be met 
without reducing the cupola below 40 inches diameter at the 
tuyeres, then the air chamber should be placed on the outside, 
and any desired boshing of the cupola made by placing com- 
mon red brick behind the fire-brick lining. 

When the air chamber is placed upon the outside of the 
shell, it may be formed by a round cast iron or sheet metal 
pipe extending around the cupola, with branches extending 
down to each tuyere ; or it may be made of boiler plate and 
riveted to the shell. The great objection to the round or over- 
head air chamber is the numerous joints required in connecting 
it with each tuyere. These joints require continual looking 
after to prevent leakage of blast, and in many cases they are 
not examined from one year's end to another, and a large per 
cent, of the blast is frequently lost through leaky joints. The 
best air chambers are those made of boiler plate and riveted to 
the cupola shell and securely corked. These air chambers 
are made of any shape that may suit the fancy of the construc- 
tor, and in many cases are very much in the way of the melter 
in making up the cupola and of the moulders in removing the 
molten iron. They should not be made to extend out from the 
shell more than six inches, and any air capacity desired given 
by extending the chamber up or down the shell. The air 
capacity should not be less than three or four times the area of 
the outlet of the blower, and may be much larger. The blast 



1 6 THE CUPOLA FURNACE. 

should be admitted to the chamber from the top on each side 
of the cupola. This arrangement places the pipes out of the 
way where they are least likely to be knocked and injured. 
When the tuyeres are placed low, the chamber may be made 
to extend down to the bottom plate. In this case, the bottom 
plate must be made larger and the chamber cut away front and 
back for the tap and slag holes. 

When the tuyeres are placed high, the chamber should be 
placed up out of the way of the tap and slag holes, and riveted 
to the shell at both top and bottom. An opening should be 
made in the air chamber under each tuyere and covered with a 
piece of sheet lead, so that any molten iron or slag running into 
the chamber from the tuyeres will flow out and not injure or 
fill up the chamber. An opening should be placed in front of 
each tuyere for giving draught to the cupola when lighting up, 
and for the removal of any iron or slag that may run into the 
tuyere during a heat. These openings should not be made 
over three or four inches in diameter, and should each be pro- 
vided with a tight-fitting door to prevent the escape of the blast. 

TAP HOLE. 

One or more orifices are placed in the casing at the bottom 
plate for the removal of the molten iron from the cupola. 
These openings are known as tap holes, and in the casing are 
from six to eight inches wide and seven to nine inches high, 
curved or rounded at the top. The opening through the 
cupola lining is generally formed by the brick and presents a 
very ragged appearance after the lining has been in use a short 
time. This opening should be lined with a cast iron casting 
bolted to the cupola casing, and made to extend almost 
through the lining. The casing should be made slightly taper- 
ing with the large end inside, or ribbed, to prevent the front 
being pushed out by the pressure of molten iron retained in 
the cupola. For small cupolas, or a large cupola from which 
the iron is removed in large ladles, but one tap hole is required. 
But large cupolas melting over eight tons of iron per hour, 



CONSTRUCTING A CUPOLA. 1 7 

from which the iron is taken in hand ladles, require two tap 
holes. Two tap holes are sometimes placed in a cupola on 
opposite sides to shorten the distance of carrying the iron to 
the moulds. And two tap holes are also sometimes placed 
side by side so that each may be kept in better order through 
the heat. This is bad practice, for if the front is properly put 
in, one tap hole will run ofT all the iron a cupola is capable of 
melting. When two tap holes are put in they should be placed 
one in front and the other in the back or side of the cupola, so 
that the moulders will not be in each other's way when catch- 
ing-in. 

THE SPOUT. 

A short spout must be provided for conveying the molten 
iron from the tap hole to the ladles. This spout is generally 
made of cast iron, and is from six to eight inches wide with 
sides from three to six inches high, and for small ladle work is 
from one to two feet long. For large ladle work it is made 
much longer. In some foundries where a long spout is only 
occasionally required, the spout is made in two sections and 
put together with cleats, so that an additional section may be 
put up to fill a large ladle and taken down when it is filled. The 
spout should be long enough to throw the stream near the 
center of the ladle when filling. In a great many foundries 
the spout is laid upon the bottom plate, and only held in place 
by the making up of the front, and is removed after each heat. 
This entails the loss of a great deal of spout material each heat, 
and sometimes the spout is struck in the careless handling of 
ladles and knocked out of place, when much damage may be 
done. When not in the way of removing the dump, the spout 
should be securely bolted to the bottom plate. 

When it is desired to run a very small cupola for a greater 
length of time than an hour and a half, or a large cupola for a 
longer time than two hours and a half, slag must be tapped to 
remove the ash of the fuel and dross of the iron from the 
cupola, to prevent bridging over and bunging up. The slag 

2 



1 8 THE CUPOLA FURNACE. 

hole from which the slag is tapped is placed between the 
tuyeres, and below the lower level of the lower row of tuyeres. 
A hole is cut through the casing and lining from three to four 
inches in diameter, and a short spout or apron is provided to 
carry the slag out, so that it will fall clear of the bottom plate. 
The slag hole should be placed at the back of the cupola, or at 
the greatest possible distance from the tap hole, so that the 
slag will not be in the way of the moulders when catching the 
iron. The height at which a slag hole should be placed above 
the sand bottom depends upon how the iron is tapped. The 
slag in a cupola drops to the bottom and floats upon the sur- 
face of the molten metal, and rises and falls with it in the 
cupola. If the molten iron is held in the cupola until a large 
body accumulates, the slag hole must be placed high and the 
slag tapped when it has risen upon the surface of the molten 
iron to the slag hole. When the iron is withdrawn, the slag 
remaining in the cupola falls below the slag hole, and the hole 
must be closed with a bod to prevent the escape of blast. If 
the iron is drawn from the cupola as fast as melted, the slag 
hole is placed two or three inches above the sand bottom at the 
back of the cupola. The slag then lies upon the molten iron, 
or upon the sand bottom, and the slag hole may be opened as 
soon as slag has formed, and allowed to remain open through- 
out the heat. 

TUYERES. 

A number of openings are made through the casing and lin- 
ing near the bottom of the cupola for admitting the blast into 
the cupola from the air chamber or blast pipe. These open- 
ings are known as tuyeres. Tuyeres have been designed of all 
shapes and sizes, and have been placed in cupolas in almost 
every conceivable position, so there is little to be learned by 
experimenting with them, and the only things to be considered 
are the number, shape, size and position of tuyeres for different 
sized cupolas. For a small cupola, two tuyeres are sufficient. 
A greater number promotes bridging. They should be 



CONSTRUCTING A CUPOLA. I9 

placed in the cupola on opposite sides, so that the blast will 
meet in the center of the cupola, and not be thrown against the 
lining at any one point with great force. The best shape for a 
small cupola is a triangular or upright-slot tuyere. These 
cause less bridging than the flat-slot or oval tuyere, and in 
small cupolas make but little difference in the amount of fuel 
required for the bed. When only two tuyeres are provided, a 
belt air chamber around the cupola is not required, and the 
blast pipes are generally connected direct with each tuyere. 
In large cupolas, the shape of the tuyeres selected makes but 
little difference in the melting, so long as they are of sufficient 
size and number to admit the proper amount of blast to the 
cupola, and so arranged as to distribute it evenly to the stock. 
The flat-slot or oval tuyeres are generally selected for the 
reason that they require less bed than the upright-slot tuyere. 

The number of tuyeres required varies from four to eight, 
according to the size of the cupola and tuyeres. They should 
be of the same size and placed at uniform distances apart. A 
tuyere should never be placed directly over the tap or slag hole. 
The combined tuyere area should be from two to three times 
greater than the area of the blower outlet. The tuyere boxes 
or casings are made of cast iron, and should be bolted to the 
cupola shell to prevent any escape of blast through the lining 
when it becomes old and shaky, or when lined with poor 
material and the grouting works out, as is sometimes the case. 

The height at which tuyeres are placed in cupolas above the 
sand bottom varies from one or two inches to five feet, and 
there is a wide difference of opinion among founders as to the 
height at which they should be placed. When the tuyeres are 
placed low, the iron must be drawn from the cupola as fast as 
melted, to prevent it running into the tuyeres. In foundries 
where the iron is all handled in hand-ladles, this can readily be 
done, and the tuyeres are placed low to reduce the quantity of 
fuel in the bed and make hot iron. In foundries in which 
heavy work is cast, and the iron handled in large ladles, the 
tuyeres are placed high, so that a large amount of iron may be 



20 THE CUPOLA FURNACE. 

accumulated in the cupola to fill a large ladle for a heavy piece 
of work. 

We do not believe in high tuyeres, and claim they should 
never be placed more than lo or 12 inches above the sand 
bottom for any kind of work ; and if slag is not to be tapped 
from the cupola, they should not be placed more than two or 
three inches above the sand bottom. In stove foundries, in 
which cupolas of large diameter are employed and hot iron re- 
quired throughout the heat, the tuyeres are placed so low that 
the sand bottom is made up to within one inch of the bottom 
of the tuyeres on the back, and two or three inches at the front. 
This gives plenty of room below the tuyeres for holding iron 
without danger of it running into the tuyeres. In cupolas of 
small diameter, two inches is allowed at the back and three or 
four inches at the front. This insures a hot, even iron through- 
out the heat, if the cupola is properly charged, and a much less 
quantity of fuel is required for the bed than if the tuyeres were 
placed high. Molten iron is never retained in the cupola for 
this class of work, and the tap hole is made of a size to let the 
iron out as fast as melted and the stream kept running through- 
out the heat. 

Cupolas with high tuyeres are not employed for this class of 
work, for they do not produce a hot fluid iron throughout a 
heat without the use of an extraordinarily large per cent, of 
fuel, and when the tuyeres are extremely high they do not 
make a hot iron with any amount of fuel. Nothing is gained 
by holding molten iron in a cupola, for iron can be kept hotter 
in a ladle than in a cupola, and melted hotter with low than 
high tuyeres, and a cupola is kept in better melting condition 
throughout a heat by tapping the iron as fast as melted. 

TWO OR MORE ROWS OF TUYERES. 

It is the common practice to place all the tuyeres in a cupola 
at the same level, or in one row extending around the cupola. 
But two or more rows are frequently placed one above the 
other. When a large number of rows are employed, they 



CONSTRUCTING A CUPOLA. 21 

decrease in area gradually from the lower to the top tuyere, 
and the rows are generally placed very close together. When 
two rows are put in, the second row is made from one-half to 
one-tenth the area of the first row, and the two rows are placed 
from 8 to 1 8 inches apart. If the area of the second row is 
one-half that of the first, it is generally placed from 8 to lo 
inches above the first row, and only when the tuyeres are very 
small are they placed at a greater height above the first row. 
When three rows are put in, the second row is made one-half 
the area of the first row, and the third row one-fourth the area 
of the second, and the rows are placed from 6 to lO inches 
apart. When tuyeres are placed in a cupola all the way up 
to the charging door, those above the first or second rows are 
made one inch diameter, and are placed from I2 to 14 inches 
above each other. 

The tuyere in the upper row may be placed directly over the 
tuyere in the row beneath it, or may be placed between two 
lower ones. Some cupola men claim that much better results 
are obtained by this latter plan, but we have never observed that 
it made any difference whether they were placed over or be- 
tween those of the lower rows. 

Faster melting is secured with two or three rows of tuyeres 
than with one row in cupola of the same diameter, and the 
melting capacity per hour is increased about one-fourth in 
melting large heats. When melting a small heat for the size of 
the cupola, nothing is gained by the additional rows of tuyeres, 
since a much larger quantity of fuel is required in the bed, for 
which there is no recompense by saving of fuel in the charges 
through the heat, and fast melting is seldom any great object 
in small heats. 

LINING, 

The casing may be lined with fire-brick, soapstone or other 
refractory substances. In localities where fire-brick cannot be 
obtained, native refractory materials are used; but fire-brick 
are to be preferred to native mineral substances. Cupola brick 



22 THE CUPOLA FURNACE. 

are now made of almost any shape or size required in cupola 
lining, and can be purchased at as reasonable a price as the 
common straight fire-brick. The curved brick, laid flat, make 
a more compact and durable lining than the wedge-shaped 
brick set on end, and are most generally used. When laying 
up a lining, the grouting or mortar used should be of the same 
refractory material as the brick, so that it will not burn out and 
leave crevices between the brick, into which the flame pene 
trates and burns away the edges of the brick. This material is 
made into a thin grout, and a thin layer is spread upon the 
bottom plate. The brick is then taken in the hand, one end 
dipped in the grout, and laid in the grout upon the plate. 
When a course or circle has been laid up, the top is slushed 
with grout to fill up all the cracks and joints, and the next 
course is laid up and grouted in the same way. The joints are 
broken at each course, and the brick are laid close together to 
make the crevice between them as small as possible, and pre- 
vent the flame burning away the corners in case the grouting 
materia] is not good and burns out. 

Brick that do not expand when heated are laid close to the 
casing. Those that do expand are laid from a fourth of an 
inch to an inch from the casing, to give room for expansion, 
and the space is filled in with sand or grout. Brick of un- 
known properties should always be laid a short distance from 
the casing, to prevent it being burst by expansion of the 
lining. 

The lining is made of one thickness of brick, and a brick is 
selected of a size to give the desired thickness of lining. In 
small cupolas, a four or five-inch lining is used, and in large 
cupolas a six or nine-inch lining. A heavier lining than nine 
inches is seldom put in, except to reduce the diameter of the 
cupola or prevent the heating of the shell. In these cases, a 
filling or false lining of common red brick is put in between the 
fire-brick and shell. The stack lining is seldom made heavier 
than four inches for any sized cupola, as the wear upon it 
is not very great, and a four-inch lining lasts for a number of 



CONSTRUCTING A CUPOLA. 



23 



years. The stack lining is laid up and grouted in the same 
way as the cupola lining. 

ARRANGEMENT OF BRACKETS, ETC. 

In Fig. I is shown the manner in which brackets or angle 
iron are put into a cupola for the support of the lining in sec- 
tions upon the casing. The brackets are made of heavy boiler 
plate from five to six inches wide, circled to fit the casing and 

Fig. I. 




SECTIONAL VIEW OF CUPOLA. 



bent at a square angle. The part riveted to the casing is made 
four inches long and secured to the casing with two or three 



24 THE CUPOLA FURNACE. 

rivets. The bracket or shelf for the support of the lining is 
made from one and a half to two inches long. The brackets 
are placed about two feet apart around the casing and in rows 
from two to three feet above each other. These brackets are 
but little in the way when laying up a lining, and support the 
latter so that a section may be taken out and replaced without 
disturbing the remainder of the lining. 

Angle iron is by many preferred to brackets for the support 
of the lining. It is put in bands extending all the way around 
the casing and riveted to it. These bands not only support the 
lining but act as a brace to the casing, and in some respects are 
a better support for the lining than brackets. They catch and 
hold in place all the grouting or sand that may work out of the 
lining between the casing, and give a more even support to the 
lining, but with their use it is sometimes more difficult to fit the 
brick around when laying up a lining. Still, angle iron has gener- 
ally taken the place of brackets and is put in all the modern 
cupolas. The brackets or angle iron should not be made to 
extend out from the casing more than one and a half or two 
inches, for if they do they are liable to be burned off when the 
lining becomes thin and let the iron or heat through to the cas- 
ing. One and a half inches are sufficient to support the lining 
if the brick form a circle to fit the casing.' No supports should 
be put in at the melting zone, for the lining frequently burns 
very thin at this point, even in a single heat. It is not necessary 
to put in any below the melting zone, and the first one should 
be placed at the upper edge of the zone, and from this up they 
should be put in at every two or three feet. 

The weight of brick placed upon the lower courses in a 
cupola lining is sufficient to crush most of the soft cupola brick, 
and were it not for the support given to three sides of them in 
the lining they would, by the great weight placed upon them, 
be reduced to a powder. As a lining burns out it becomes 
thin more rapidly at the bottom, and it often happens that the 
lining at the melting zone is reduced to one-half its thickness, 
or even less, in a few heats, and this reduced lining often has to 



CONSTRUCTING A CUPOLA. 2$ 

support a lining of almost full thickness for the entire cupola, 
and in some cases also the stack lining. The cohesive force of 
these bricks is reduced by the intense heat in the cupola, and 
when subjected to so great a pressure and heated they are 
crushed and the lining gradually settles and becomes shaky. 
This settling is so great with some qualities of brick that in 
cupolas having no frame riveted to the casing around the 
charging aperture, the arch over the door frequently settles so 
low that it becomes necessary to rebuild it to maintain the full 
size of the opening. 

Brick do not give the best results when subjected to so great 
a pressure and heated to a high temperature. Therefore, in all 
cupolas, brackets or angle iron should be put in every two or 
three feet for the support of the lining on the casing, and the 
casing should be made heavy enough to support the entire 
lining when a section has been burned out or removed. 

In the illustration (Fig. i ) is also shown a way for reducing the 
size and weight of the bottom doors and preventing the casing 
from rusting off at the bottom. In many of the large cupolas re- 
quiring heavy sand bottoms, the bottom plate can be made to 
extend into the cupola from three to six inches all round with- 
out in the least interfering with dumping, and the first few 
courses of brick sloped back from the edge of the plate to the 
regular thickness of lining to prevent sand lodging on the edges 
of the plate around the lining. By this arrangement in large 
cupolas the diameter of the doors may be reduced from six to 
ten inches and very much lightened, and less sand will be re- 
quired, for the sand bottom and the dump falls as freely as 
when the doors are the full size of the cupola. 

Cupolas that are not in constant use absorb a great deal of 
moisture into the lining and are constantly wet around the 
bottom plate, and light casings are eaten away by rust in a 
short time. To prevent this the first one or two courses of 
brick can be laid a few inches from the casing and a small air 
chamber formed around the cupola at this point. If this 
chamber is supplied with air from a few small holes through 



26 THE CUPOLA FURNACE. 

the iron bottom or casing, the latter is kept dry and rusting 
is prevented. 

In the illustration (Fig. i) is shown the triangular-shaped 
tuyere in position in the lining. This tuyere prevents bridging 
to a greater extent than any other, and is, for a small cupola, 
one of the very best shapes. It is formed with a cast iron 
frame set in the lining, and each tuyere may be connected with 
a separate pipe, as shown, or they may be connected with an 
air belt extending around the cupola. 

Bottom plates may be cast with a light flange around the 
edge, as shown in the illustration (Fig. i), or made perfectly 
flat on top ; but it is better to cast them with a small flange or 
bead for holding the shell in place upon the plate, and thus 
cause the cupola to have a more finished look around the 
bottom. 

FIRE PROOF SCAFFOLDS. 

The charging door or opening through which fuel and iron 
are charged into a cupola is placed at so great a height from 
the floor that it is necessary to construct a platform or scaffold, 
upon which to place the stock, and from which to charge it 
into the cupola. For heavy work, this scaffold is generally 
placed on three sides of the cupola, leaving the front clear for 
the swinging of crane ladles to and from the spout ; but for 
light work the scaffold frequently extends all the way around 
the cupola to give more room for placing stock upon it. The 
distance the floor of a scaffold is generally placed below the 
charging door is about two feet, but that distance varies, and 
floors are frequently placed on a level with the door or three 
or four feet below it to suit the kind of iron to be melted or the 
facilities for placing stock upon the scaffold from the yard. 
The scaffold and its supports are more exposed to fire than 
almost any other part of a foundry, for live sparks are thrown 
from the charging door upon the scaffold floor, and molten 
iron, slag, etc., are frequently thrown against its supports and 
the under side of the floor with considerable force when dump- 



CONSTRUCTING A CUPOLA. 2/ 

ing the cupola. Numerous plans have been devised to make 
scaffolds fire-proof and prevent the foundry from being 
set on fire. In many of the wooden foundry buildings 
the scaffold is constructed entirely of wood, and to render 
it fire-proof the supports and under side of the floor are 
covered with light sheet iron to protect them from molten 
iron, slag, etc., when dumping. The covering of the wood- 
work of a scaffold in this way is very bad practice, for while 
it protects the wood from direct contact with the fire, it 
also prevents it from being wetted, and in a short time the 
wood becomes very dry and very combustible. The thin 
covering of sheet iron is soon eaten away with rust, leaving 
holes through which sparks may pass and come in contact with 
the dry wood and ignite it under the sheet iron where it cannot 
be seen, and the cupola men, after wetting down the dump very 
carefully, may go home leaving a smoldering fire concealed by 
the sheet iron covering which may break forth during the night 
and destroy the foundry. It is better to leave all the wood- 
work entirely uncovered and exposed to the fire and heat, and 
wet it in exposed places before and after each heat ; the wood 
is then kept dampened and is not so readily combustible as 
when covered with sheet iron, and if ignited the fire may be 
seen and extinguished before the men leave for home after their 
day's work is done. At many of the wooden foundry buildings 
the cupola is placed outside the foundry building and a small 
brick house or room constructed for it and the molten iron run 
into the foundry by a cupola spout extending through the wall. 
In this way a scaffold may be made entirely fire-proof by put- 
ting in iron joist and an iron or brick floor, and putting on an 
iron roof. We saw a scaffold and cupola house at a small foundry 
in Detroit, Mich., about twenty years ago, that was constructed 
upon a novel plan and was perfectly fire-proof. The house was 
twelve feet square and constructed of brick, the scaffold floor 
was of iron and supported by iron joist, the walls were perpen- 
dicular to five feet above the scaffold floor, and from this point 
they were contracted and extended up to a sufficient height to 



28 THE CUPOLA FURNACE. 

form a stack three feet square at the top. The cupola was placed 
at one side of this room and the cupola-house, and the spout 
extended through the wall into the foundry ; the open top of the 
cupola extended about two feet above the scafTold floor, and its 
stack was formed by the contracted walls of the cupola-house. 
There were no windows in the house, and only one opening 
above for placing stock upon the scafifold and one below for re- 
moving the dump and making up the cupola, both of which 
openings were fitted with iron door frames and doors, and 
could be tightly closed. When lighting up, the scaffold door 
was closed to give draught to the cupola, and when burned up 
the door was opened and the cupola charged from the scafifold. 
Sparks from the cupola when in blast fell upon the scafifold 
floor and were never thrown from the top of the stack or cupola- 
house upon the foundry roof or the roofs of adjoining build- 
ings, and when the doors were closed the scafifold was as fire- 
proof as a brick stack. The great objection to this scaffold was 
the gas from the cupola upon the scafifold when the blast was 
on, and the intense heat upon the scafifold in warm weather or 
when the stock got low in the cupola. 

The best and safest scafifolds are those constructed entirely 
of iron, or with brick floors and supported by iron columns, or 
brick walls and made of a sufificient size to admit of wood or 
other readily combustible cupola material being placed at a safe 
distance from the cupola. The cupola scafifold in the foundry 
of Gould & Eberhardt, Newark, N. J., is constructed of iron 
supported by iron columns and brick walls, and is of sufificient 
size and strength to carry two car-loads of coke, one hundred 
tons of pig and scrap iron, and all the wood shavings and other 
material required for the cupola. In the new iron foundry 
building recently erected by The Straight Line Engine Com- 
pany, Syracuse, N. Y., the scafifold is constructed entirely of iron 
and supported by the iron columns which support the foundry 
roof. It extends the entire length of the foundry, afifording 
ample room for storing iron, coke, wood, and all cupola sup- 
plies, thus doing away with a yard for storing such material, and 



CONSTRUCTING A CUPOLA. 29 

placing them under the foundry roof and convenient for use. 
Scaffolds of this kind greatly reduce the expense of handling 
cupola stock, and also reduce the rate of insurance of foundry 
buildings. 



CHAPTER III. 

CUPOLA TUYERES. 

The cupola furnace may be supplied with the air required 
for the combustion of the fuel by natural draft induced by a 
high stack, a vacuum created by a jet of steam, or by a forced 
blast from a fan or blower. In either case the air is generally 
admitted to the cupola through openings in the sides near the 
bottom. These openings are known as tuyeres or tuyere holes. 
The location, size, number and shape of these tuyeres are a mat- 
ter of prime importance in constructing a cupola, and are a sub- 
ject to which a great deal of attention has been given by 
eminent and practical foundrymen for years, and to these men 
is due the credit for the advancement made in the construction 
of cupolas. 

It is only a few years since lo to 15 tons was considered a 
large heat for a cupola, and when a large casting was to be 
poured two or more cupolas were run at the same time and the 
greater part of a day consumed in melting. Now 60 tons are 
melted in one cupola in four hours for light foundry work, and 
hundreds of tons are melted in one cupola in steel works with- 
out dropping the bottom. This improvement in melting is 
largely due to the improvement in the size, shape and arrange- 
ment of tuyeres. 

There have been epidemics of tuyere inventing several times 
in this country in the past twenty-five years, and during these 
periods it has been almost impossible for an outsider to get a 
look into a cupola for fear the great secret of melting would be 
discovered in the shape of the tuyere and made public. Dur- 
ing these epidemics tuyeres of almost every conceivable shape 
have been placed in cupolas, and great results in melting 

(30) 



CUPOLA TUYERES. 3 I 

claimed for them. Many of these tuyeres were soon found to 
be compHcated and impracticable, or the advantage gained by 
their use in melting was more than ofTset by extravagant use 
of fuel. 

It would be useless for us to describe all the tuyeres we have 
seen employed, for many of them were never used out of the 
foundry in which they were invented, and only used there for a 
short time. We shall, therefore, describe only a few of those that 
have been most extensively used or are in use at the present 
time. 

The round tuyere is probably the oldest or first tuyere ever 
placed in a cupola. It was used in cupolas and blast furnaces 
in Colonial days in this country, and long before that in France 
and other countries. In the old-fashioned cast iron stave 
cupolas three round tuyeres were generally placed in a row, 
one above another, on opposite sides of the cupola. The first 
or lower tuyere was placed from i8 to 24 inches above the 
sand bottom, and the others directly over it from 3 to 4 inches 
apart. The tuyere nozzle or elbow was attached to the blast- 
pipe by a flexible leather hose, and first placed in the lower 
tuyere and the two upper tuyeres temporarily closed with clay. 
When a small heat was melted the nozzle was permitted to re- 
main in the lower tuyere through the heat. But when a large 
heat was melted and the cupola melted poorly at any part of 
the heat, or if molten iron was to be collected in the cupola for 
a large casting, the clay was removed from the upper tuyeres, 
and the nozzle removed from one to the other, as required, and 
the lower tuyeres closed with clay. 

In these cupolas the tuyeres were generally too small to ad- 
mit a proper volume of blast to do good melting. In one of 
28 inches diameter we recently saw at Jamestown, N. Y., the 
original tuyeres were only 3 inches in diameter. Two tuyeres 
of this size could not possibly admit a sufficient volume of blast 
to do good melting in a cupola of the above diameter, and in 
this one they had been replaced by two of a much larger diam- 
eter placed at a lower level than the old ones. The round 



32 



THE CUPOLA FURNACE. 



tuyere is still extensively used in small cupolas where the 
tuyeres can be made of a diameter not to exceed 5 or 6 inches, 
but in large cupolas it has generally been replaced by the flat 
or oval tuyere, which admits the same volume of blast and per- 
mits of a smaller amount of fuel being used in the bed than 
could be used with a round tuyere of large area, 

OVAL TUYERE. 

In Fig. 2 is shown the oval or oblong tuyere now extensively 
used. It is made of different sizes to suit the diameter of 
cupola, the most common sizes used being 2x6, 3x8, and 
4x12 inches. They are laid flat in the lining and generally 
supplied from an outside belt air chamber. This tuyere is the 
one most commonly used by stove, bench and other foundries 
requiring very hot iron for their work. They are placed very 
low, generally not more than two or three inches above the 
sand bottom, and in large cupolas the slope of the bottom fre- 
quently brings it up to the bottom of the tuyeres on the back 
side of the cupola. This tuyere admits the blast to a cupola 
as freely as a rounded tuyere of the same area, and the tendency 
of the stock to chill over the tuyeres in settling and bridge the 
cupola is no greater than with a round tuyere of the same 
capacity. It admits of a lower bed than the round tuyere, 
and is to be preferred to the round form for cupolas requir- 
ing tuyeres of larger area. 

EXPANDED TUYERE. 

In Fig. 3 is seen the expanded tuyere, which is made larger 



Fig. 3. 



Fig. 2. 





CUPOLA TUYERES — OVAL TUYERE. EXPANDED TUYERE. 

at the outlet than at the inlet. It is reduced at the inlet so 



CUPOLA TUYERES. 33 

that the combined tuyere area may correspond with the outlet 
of the blower and equalize the volume of blast entering the 
cupola at each tuyere from the air belt. It is expanded at the 
outlet to permit the blast to escape freely from the tuyeres into 
the cupola, and in case the stock settles in the front of the 
tuyere in such a way as to close up part of it, there may still be 
sufficient opening for the full volume of blast entering the 
tuyere to pass into the cupola. The tuyere is made from two 
to four inches wide at the inlet and six to twelve inches long. 
The width of the outlet is the same as that of the inlet, and the 
length of the outlet is from one-fourth to one-half longer than 
the inlet. The tuyere is laid flat in the lining, the same as the 
oval tuyere, and the only advantage claimed for it over that 
tuyere is that it cannot be closed so readily by the settling of 
the stock and the chilling of the iron or cinder in front of it. 
The expanded tuyere is preferred by many to the oval tuyere 
on this account and is extensively used at the present time. 

DOHERTY TUYERE. 

In Fig. 4 is seen the Doherty arrangement of tuyeres, designed 
by Mr. Doherty of the late firm of Bement & Doherty, Philadel- 
phia, Pa., and employed in the Doherty cupola, a cupola that was 
extensively used in Philadelphia about twenty-five years ago. 
The arrangement consists of two or more round tuyeres placed 
in the lining and at an angle to it, instead of passing straight 
through the lining as tuyeres generally do. The blast pipes 
connecting with each tuyere were placed at the same angle as 
the tuyere, the object being to give the blast a whirling or 
spiral motion in the cupola. The blast took the desired course, 
as could be plainly seen by its action at the charging door, and 
it had the appearance of making a more intense heat in the 
cupola than when delivered from the straight tuyere. But this 
appearance was deceptive, and after careful investigation it was 
found that no saving in fuel was effected or faster or hotter 
melting done on account of this motion of the blast. The 
cupolas and tuyeres were, however, constructed of proper pro- 
3 



34 THE CUPOLA FURNACE. 

portions, and were a decided improvement on the small tuyere 
cupolas in use at that time. Many of them were placed in 
foundries and are still in use, but no importance is attached to 
the spiral motion of the blast. 

SHEET BLAST TUYERE. 

In Fig. 5 is seen the horizontal slot tuyere. This tuyere 
Fig. 4. 



Fig. 5. 





SHEET BLAST TUYERE. 
DOHERTY TUYERE. 

consists of a slot from one to two inches wide, extending one- 
third around the cupola on each side, or a continuous slot ex- 
tending all the way around the cupola. The slot is formed by 
two cast iron plates, on one of which are cast separating bars 
to prevent the plates being pressed together by the weight of 
the lining or warped by the heat. This tuyere is known as the 
sheet blast tuyere. It admits of a smaller amount of fuel being 
used for a bed than any other tuyere placed in a cupola at the 
same height above the bottom. It distributes the blast equally 
to the stock, and does fast and economical melting in short 
heats. But the tendency of the cupola to bridge is greater 
than with almost any other tuyere, and a cupola with this 
tuyere cannot be run successfully for a greater length of time 
than two hours. 

MACKENZIE TUYERE. 

In Fig. 6 is seen the Mackenzie tuyere, designed by a Mr. 
Mackenzie of Newark, N. J., and used in the Mackenzie cupola. 
This is a continuous slot or sheet blast tuyere, but differs from 



CUPOLA TUYERES. 



35 



the one just described in that the cupola is boshed and the 
bosh overhangs the slot from four to six inches. The slot is 
protected by the overhanging bosh and cannot be closed up by 




SHELL ANGLE IRON 




BED PLATE ^- 




MACKENZIE TUYERE. 



the settling of the stock. The Mackenzie cupolas with this 
tuyere are constructed of an oval or oblong shape, with an inside 
belt air chamber. The blast enters the air chamber from a tuyere 
box at each end of the cupola, and passes into the cupola 
through a two-inch slot extending all the way round the cupola. 



BLAKENEY lUYERE. 



In Fig. 7 is seen the Blakeney tuyere used in the Blakeney 
cupola constructed by The M. Steel Company, Springfield, Ohio. 



36 



THE CUPOLA FURNACE. 



This tuyere is a modification or an improvement on the sheet 
blast tuyere, and extends all the way around the cupola. It is 

Fig. 7. 




BLAKENEY TUYERE. 

supplied from an outside belt air chamber riveted to the shell. 
The blast is conducted to the air chamber through one pipe, 
and, striking the blank spaces sidewise in rear of chamber, 
passes all around through the curved tuyeres into the centre of 
the furnace. This tuyere admits the blast freely and evenly to 
the cupola and very good melting is done with it. All the 
tuyeres described above may be used with either coal or coke. 

HORIZONTAL AND VERTICAL SLOT TUYERE. 

In Fig. 8 is seen the horizontal and vertical slot tuyere. 

Fig. 8. 




HORIZONTAL AND VERTICAL SLOT TUYERE. 

This was designed for coke, and we have seen it used in but 
one cupola, a 40-inch one. One tuyere was placed on each 



CUPOLA TUYERES. 



37 



side of the cupola. The horizontal slot of each tuyere, i inch 
wide, extended one-third way round the cupola, and the 
vertical slots, i inch wide and 12 inches long, were placed 
above it as shown. The tuyere did excellent melting, and the 
cupola could be run for a long time without bridging. 

REVERSED J TUYERE. 

In Fig. 9 is seen a vertical and horizontal slot or reversed T 
tuyere, also used for coke. The slots in this tuyere are from 
two to three inches wide and ten to twelve inches long. From 
two to eight of these tuyeres are placed in a cupola, according 
to the diameter. This tuyere has been extensively used, and 
is said to be an excellent tuyere for coke melting. 



Fig. 9. 



Fig. 10. 



Fig. II. 






REVERSED T TUYERE. 



VERTICAL SLOT TUYERE. VERTICAL SLOT TUYERE. 



In Figs. 10 and 11 are seen the vertical slot tuyeres used 
principally in cupolas of small diameter to prevent bridging. 
They are made from two to three inches wide and ten to 
twelve inches long, and two or more are placed in a cupola at 
equal distances apart. 

TRUESDALE REDUCING TUYERE. 

In Fig. 12 is seen the Truesdale reducing tuyere designed 
by a Mr. Truesdale of Cincinnati, Ohio, and extensively used in 
cupolas in that vicinity about 1874. The tuyere consisted of 
one opening or tuyere placed directly over another until six, 
eight or ten tuyeres were put in. The lower tuyere was made 



38 



THE CUPOLA FURNACE. 



Fig. 13. 



Fig. 14. 



three or four inches in diameter, and tuyeres above it were 
placed one inch apart, and each one made of a smaller diam- 



FlG. 12. 

O 

o 
O 

O 
O 

O 
O 

o 





TRIANGULAR TUYERE. 



TRUESDALE REDUCING 
TUYERE. 



LAWRENCE REDUCING 
TUYERE. 



eter until they were reduced to one inch. The bottom row of 
tuyeres were placed two, four and six inches apart, and the 
tuyeres in each succeeding row were placed further apart, were 
of a smaller diameter and admitted less blast to the cupola to- 
ward the top of the bed than at the bottom. The cupolas were 
generally boshed, and the tuyeres supplied from an inside belt 
air chamber, formed of cast iron staves, to which the tuyeres 
were attached by cleats or dovetails cast on the stays. Very 
fast melting was done in cupolas with this tuyere, but the ten- 
dency to bridge in cupolas of small diameter is so great that 
it could not be used. In large cupolas, however, it gave ex- 
cellent results, and is still in use in numerous foundries. 



LAWRANCE REDUCING TUYERE. 



In Fig. 13 is seen the Lawrance reducing tuyere designed by 
Frank Lawrance of Philadelphia, Pa., and used in the Lawrance 
cupola, built by him. This tuyere was designed for either coal 
or coke melting, and works equally well with either. The 



CUPOLA TUYERES. 39 

opening at the bottom is from 3 to 4 inches square, and the 
slot from 10 to 12 inches long, from i to i ^ inches wide at the 
bottom, and tapers to a point at the top. The tuyeres are placed 
in the cupola from 6 to 12 inches apart, and supplied from a belt 
air chamber inside the casing. The air chamber in this cupola 
was first formed with cast iron staves, and the tuyeres held in 
place by cleats cast upon the staves. But the staves were 
found to break after repeated heating and cooling, and a boiler 
iron casing is now used for the air chamber. This tuyere and 
cupola do excellent melting, and a great many of them are 
now in use. 

TRIANGULAR TUYERE. 

In Fig. 14 is seen the triangular tuyere, designed by the 
writer over 25 years ago to prevent bridging in small cupolas 
and extensively used in both small and large cupolas, with 
either coal or coke. This tuyere may be made with the base 
and sides of the tuyere of an equal length, forming an equilat- 
eral triangle, or the sides may be made longer than the base, 
bringing the tuyere up to a sharp point at the top to prevent 
bridging ; or the sides may be extended up to a sufficient height 
to form a reducing tuyere. 

The Magee Furnace Company, Boston, Mass., placed this 
tuyere in their large cupola, constructed to melt iron for stove 
plate, about twelve years ago, and it has been in constant use 
ever since, giving excellent results in melting with coal and 
coke. In this cupola, which is 5 feet 4 inches diameter at the 
melting point, the tuyere is 9 inches wide at the base and 16 
inches high. It was not thought best to extend the tuyere up 
to a point at so sharp an angle, and the top was cut off", leaving 
the opening 2 inches wide at the top. This tuyere has been 
arranged to take the place of the Truesdale reducing tuyere, 
and has been made from 6 to 8 inches wide at base and 24 to 
30 inches high, running up to a point. It has also been used 
in imitation of the Lawrance reducing tuyere and made from 3 
to 4 inches wide at base and 12 to 16 inches high. 



40 



THE CUPOLA FURNACE. 



WATER TUYERE. 

In Fig. 15 is seen the water tuyere. This tuyere is designed 
to be used in cupolas or furnaces where the whole or part of 
the tuyere is exposed to an intense heat and liable to be melted 
or injured, as is the case with tuyeres placed in the bottom of a 
cupola or in furnaces where a hot blast is used. 

The tuyere or metal surrounding the tuyere opening is cast 
hollow and filled with water, or one end is left open and a spray 
thrown against the end exposed to the heat from a small pipe, 
as shown in illustration. The tuyere is also made with a coil 

Fig. 16. 



Fig. 15 




WATER TUYERE, 



COLLIAU TUYERE. 



of gas pipe cast inside the tuyere through which water con- 
stantly flows. The water tuyere is never used in cupolas when 
the tuyeres are placed in the sides of the cupola, but it has 
been used in cupolas in which the tuyere was placed in the 
bottom and exposed to the heat of molten iron, cinder and 
slag. When used in this way the tuyere is placed in the centre 
of the bottom and is made from i to 3 feet long, the mouth 
being placed at a sufificient height above the sand bottom to 



CUPOLA TUYERES. 4 I 

prevent molten iron or slag overflowing into it. The part of 
the tuyere" extending up in the cupola and exposed to the heat 
is protected and prevented from melting by the stream of water. 
For this purpose the coil gas pipe tuyere is better than the 
hollow or spray tuyere just described. 

COLLIAU TUYERE. 

In Fig. 1 6 is seen the CoUiau double tuyere designed by the 
late Victor Colliau of Detroit, Mich., and used in the Colliau 
cupola. In this cupola the tuyeres are placed in two rows one 
above the other in place of one row as in the ordinary cupola. 
The first row is placed at about the same height above the sand 
bottom as in the ordinary cupola and the second row from 12 
to 18 inches above the first row. The first row are flat, slightly 
expanded tuyeres similar to that shown in Fig. 2, and are made 
from 2 to 4 inches wide and 6 to 14 inches long, according to 
the size of the cupola. The tuyeres in the second row are 
made round and from 2 to 4 inches diameter. The tuyeres in 
the first row pass straight into the cupola through the lining, 
and those in the second row are pointed downward at a sharp 
angle, as shown in the cut. The object of the second row is to 
furnish sufficient oxygen to consume the escaping gases and 
create a more intense heat at the melting point than is obtained 
with the single row of tuyeres from the same amount of fuel. 

WHITING TUYERE. 

The Whiting tuyere, used in the Whiting cupola, manufac- 
tured by the Whiting Foundry Equipment Company, Chicago, 
111., was designed by Mr. Whiting, a practical foundryman of 
Detroit, Mich., as an improvement on the Colliau tuyere. The 
Whiting tuyere is a double tuyere, but differs somewhat in 
arrangement from the Colliau tuyere. The first row are flat, 
slightly expanded tuyeres, and the second row are of the same 
shape and made larger in proportion to the lower row than the 
Colliau, and the two rows are not placed at so great a distance 
apart. Both the upper and lower rows pass straight into the 
cupola. 



42 THE CUPOLA FURNACE. 

CHENNEY TUYERES. 

The Chenney tuyere, designed by the late Mr. Chenney, a 
practical foundryman of Pittsburgh, Pa., is a double tuyere 
very similar in arrangement to the CoUiau and Whiting 
tuyeres, the only difference being that both the upper and 
lower rows point downward at a sharp angle to the lining. 

THE DOUBLE TUYERE. 

The double or two rows of tuyeres appears to have first been 
designed and put into practical use about 1854 by Mr. Ireland, 
a practical English foundryman and cupola builder. In Ire- 
land's cupolas, many of which were in use in England about 
that time, the tuyeres were placed in two rows about 18 inches 
apart. Those in the upper row were of only one-third the 
diameter of those in the lower, and twice the number of 
tuyeres were placed in the upper row as were in the lower. 
The slag hole was also used by Ireland in his cupola, which 
was run for a great many hours without dumping or raking 
out, as was the custom in those days. These cupola appear 
to have given very good results in long heats, but in short 
heats they were not so satisfactory, and in more recent patents 
obtained by Mr. Ireland the upper row of tuyeres was 
abandoned. The double tuyere was also used in Voisin's 
cupola, by another English cupola designer and constructor, and 
in Woodward's steam jet cupola, also an English cupola, many 
years before they were introduced into this country by Mr. 
Colliau about 1876. 

It is claimed for the double tuyere that the second row con- 
sumes the gases which escape with the single tuyere, and, 
therefore, a great saving in fuel is efifected in melting. That a 
more intense heat is created in the cupola at the melting zone 
by the double tuyere cannot be disputed, for the destruction of 
lining is much greater at this point than with the single tuyere ; 
but on the other hand, that any saving in fuel is effected has 
not been proven by comparative tests made in melting with 
the double tuyere cupola and the single tuyere cupola, when 



CUPOLA TUYERES. 43 

properly constructed and managed. On the contrary it has 
been proven that the single tuyere cupola is the most econom- 
ical in fuel and lining. That the double tuyere melts iron 
faster than the single in cupolas of the same diameter is 
undisputed, and as between the single and double it is only 
a question whether the time saved in melting more than 
compensates for the extra expense of lining. When a double 
tuyere cupola is run to its full capacity, the consumption of fuel 
per ton of iron is about the same as the single tuyere, but in 
small heats it is much greater. This is due to the large 
amount of fuel required for a bed, owing to the great height of 
the upper tuyeres above the sand bottom ; for the bed must be 
made about the same height above the upper tuyeres as above 
the lower in a single tuyere cupola, and no greater amount 
of iron can be charged on the bed with the double tuyere 
than with the single. When constructing or ordering a double 
tuyere cupola, the smallest one that will do the work should 
be selected, so that the cupola may be run to its fullest capacity 
each heat and the best results obtained in melting. 

THREE ROWS OF 'ITJYERES. 

A number of large cupolas have been constructed with three 
rows of tuyeres, for the purpose of doing faster melting than 
can be done with the single or double tuyere cupola. Prob- 
ably one of the best melting cupolas of this kind in use at the 
present time is one constructed by Abendroth Bros., Port 
Chester, N. Y., to melt iron for stove plate, sinks, soil pipe and 
plumbers' fittings. This cupola is 6o inches diameter at the 
tuyeres and 72 inches at the charging door, and is supplied 
with blast from 36 tuyeres, placed in the cupola in three hori- 
zontal rows 10 inches apart, 12 tuyeres being placed in each row. 
The tuyeres in the first row are 6 inches square, those in the 
second row 4 inches square, and those in the third row 2 
inches square. This cupola melts 60 tons of iron in four hours, 
which is probably the fastest melting done in this country for 
the same number of hours for light work requiring hot iron. 



44 THE CUPOLA FURNACE. 

In the double or triple tuyere cupola the upper tuyeres may 
be placed directly over a tuyere in the lower row, or they may 
be placed between the tuyeres of the lower row at a higher 
level. In Ireland's cupolas double the number of tuyeres were 
placed in the upper row as were in the lower row, so that one 
was placed directly over each tuyere in the lower row and one 
between. In the modern double tuyere cupola the same num- 
ber of tuyeres are placed in each row, and the upper tuyeres 
are generally placed between those in the lower row. The 
object in placing these tuyeres in a cupola, as stated before, is 
to supply the oxygen to burn the unconsumed gases escaping 
from the combustion of fuel at the lower tuyeres. If a proper 
amount of blast is admitted at the lower tuyere the cupola is 
filled with gases at this point, and it does not make any differ- 
ence whether the upper tuyeres are placed over or between the 
lower ones, so long as the tuyeres are only to supply oxygen 
to consume the gases with which the cupola is filled. If this 
theory of producing heat by consuming the escaping gases 
from the combustion of fuel is correct, they can be consumed 
at any point in the cupola, and the row of tuyeres for this pur- 
pose should be placed above the bed, and the gas burned in 
the first charge of iron to heat it and prepare it for melting be- 
fore it settles into the melting zone. To consume these gases 
only the tuyeres should be small, and the number of tuyeres in 
the upper rows should be two or three times greater than in 
the lower row, so as to supply oxygen to all parts of the cupola, 
and not permit the gases to escape unconsumed between the 
tuyeres. If the tuyeres in the second or third rows are made 
too large in proportion to the lower row, the supply of oxygen 
is too great for the combustion of the gases, and the effect is 
to cool the iron. In the modern double tuyere cupola this 
theory is not carried out, for the tuyeres in the second row are 
made big, and admit such a large volume of oxygen at one 
point that if they were placed high their effect would be to 
cool the iron rather than heat it. But they are placed low so 
as to force the blast into the bed and give a deeper melting 



CUPOLA TUYERES. 



45 



zone, and their effect is to cause a more rapid combustion of 
fuel and do faster melting than is done in the single tuyere 
cupola of the same diameter. 



Fig. 17. 



GREINER TUYERE. 

In Fig. 17 is seen the Greiner tuyere. The novelty of this 
device consists in a judicious admission of blast into the upper 
zones of a cupola, whereby the combustible gases are con- 
sumed within the cupola and the heat utilized to pre-heat 
the descending charges, thereby effecting a saving in the fuel 
necessary to melt the iron when it 
reaches the melting zone. This de- 
vice consists of a number of upright gas 
pipes attached to the top of the wind 
box around the cupola, with branch 
pipes of I inch diameter extending into 
the cupola through the lining and 
about I foot apart, from a short dis- 
tance above the melting zone to near 
the charging door. It is claimed that 
these small pipes admit a sufficient 
amount of oxygen to the cupola to 
burn the carbonic oxide produced by 
the carbonic acid formed at the tuyeres greiner tuyere. 

absorbing carbon from the fuel in its ascent. A great saving 
in fuel is thus effected by consuming this gas and preparing 
the iron for melting before it reaches the melting zone. A 
large number of cupolas with this device are in use in Europe, 
and quite a number in this country. 

ADJUSTABLE TUYERES. 

Tuyeres are sometimes placed in a cupola so that they may 
be adjusted to conform with the size of the heat to be melted 
or the way the iron is to be drawn from the cupola, and thus 
save fuel in the bed. They are placed low when the heat is 
small or the iron is drawn from the cupola as fast as melted, 




46 THE CUPOLA FURNACE. 

and placed high when the heat is large or when iron is to be 
held in the cupola for a large piece of work. One of the best 
arranged cupolas of this kind we have seen is the cupola of the 
Pennsylvania Diamond Drill & Mfg. Company, Birdsboro, Pa. 
The air belt extending around the cupola is riveted to the shell 
about 4 feet from the bottom plate. From this belt a cast iron 
air box bolted to the shell extends down nearly to the bottom 
plate in front of each tuyere. The front of this box has a slid- 
ing door extending full length of the box. The cupola shell 
has a slot in front of each box the full length of the box. On 
each side of this slot a piece of angle iron is riveted to the shell 
to hold the lining in place. The slot is filled in with fire-brick, 
and a tuyere opening is left at any desired height from the 
bottom. When it is desired to lower the tuyere the brick are 
removed from the bottom of the tuyere and placed at the top, 
and held in place by a little stiff daubing or clay, and when it 
is desired to raise it the brick are removed from the top and 
placed at the bottom when making up the cupola. With the 
Colliau and Whiting style of air belt an adjustable tuyere can 
be arranged in this way at a very moderate cost, and foundry- 
men who think they must have their tuyeres placed high so 
they can make a large casting and only make such a casting 
once or twice a year, can save a great deal of fuel from the bed 
by having their tuyeres arranged in this way. The old plan of 
putting in two or three tuyere holes one above the other, and 
adjusting the tuyeres during the heat by raising the tuyere 
pipe from one to the other, is not practicable with the modern 
way of charging a cupola, and has long since been abandoned. 

BOTTOM TUYERE. 

In Fig. 1 8 is seen the bottom or center blast tuyere. This 
tuyere, as will be observed, passes up through the bottom of 
the cupola instead of through the sides, and admits the blast 
to the center of the cupola at the same level as the side 
tuyeres. It is not designed to change the nature of the iron 
by forcing the blast through the molten iron in the bottom of 



CUPOLA TUYERES. 



47 



the cupola, and, in fact, the blast has no more effect upon the 
quality of iron when admitted in this way than when admitted 
through side tuyeres. A tuyere when placed in the bottom of 
a cupola, unlike a side tuyere, is brought in direct contact 
with heated fuel and molten iron, and it must be made of a 
refractory material, or protected by a refractory material if 



Fig 1 8. 




BOTTOM TUYERE. 



made of metal. The tuyere shown in the cut is made of cast 
iron and is provided with a water space between the outside 
and the inside, through which a stream of water constantly flows, 
when the tuyere is in use, from a small pipe connected with a 
tank placed alongside the cupola or on the scaffold. But it 
has not been found necessary to keep the tuyere cool with 
water in short heats, for the heat in a cupola under the tuyeres 
is not sufficiently intense to melt cast iron, and the tuyere may 
be sufficiently protected against molten iron dropping upon it 
or coming in contact with it by a thick daubing of refractory 
material held in place by the prickers cast on the tuyere. 
The mouth of a bottom tuyere must be covered to prevent 



48 THE CUPOLA FURNACE. 

molten iron, slag and fuel dropping into it in their descent 
to the bottom of the cupola. This is done with a rounded 
cap placed on top of the tuyere to throw off the molten iron 
and slag, and the blast is admitted to the cupola through an 
opening around the tuyere under the cap, as indicated by the 
arrows. The tuyere must be carefully dried and daubed be- 
fore it is put in place. It cannot be attached to the bottom 
doors and must be put in place through a hole in the doors 
after they are put up, and withdrawn in the same way and 
removed before the cupola is dumped, to prevent it being 
broken or injured in falling or by the heat in the dump. It 
must have an adjustable and removable support, and the sand 
bottom must be made up very carefully around it to prevent 
leakage of molten iron. The tuyere often gets fast in the bot- 
tom and the men are frequently burned in removing it, and 
it sometimes gets filled with iron or slag, and spoils a heat. 

The bottom tuyere has been tried a great many times by 
foundrymen at different periods, and is nothing new. In con- 
versing with several old foundrymen in Massachusetts about 
20 years ago we learned that the bottom tuyere had been used 
in that State away back in the 40's, and at one time was quite 
popular with foundrymen there ; and we have met a number of 
other old foundrymen in different sections of the country who 
had tried the tuyere years ago and given it up. A bottom 
tuyere was patented by B. H. Hibler in this country August 
13, 1867. Ireland & Voisin used a bottom tuyere in their 
cupola many years ago, and had these practical men found 
any advantages in it over the side tuyere it would, no doubt, 
have been brought into general use in cupolas before this. 

The bottom tuyere was brought prominently before the 
foundrymen of this country by an ably written article by 
Thomas D. West, read before the Western Foundrymen's As- 
sociation at Chicago, 111., October 18, 1893, in which he 
describes his experiments with the tuyere and claims for it a 
great saving in fuel and cupola lining. Since the publication 
of Mr. West's article a number of foundrymen have published 



CUPOLA TUYERES. 49 

their experience with the tuyere and all claim it effects a great 
saving in lining and fuel. But if these foundrymen have not 
discovered some new feature in the tuyere that was overlooked 
by experimenters with it years ago, it will never come into 
general use. 

SIZE OF TUYERES. 

Foundrymen make a great mistake in placing small tuyeres 
in their cupolas, with a view of putting the blast into the 
cupola with greater force and driving it to the center of the 
cupola with the blower. Air may be driven from a small 
opening by a blower with greater velocity than the same vol- 
ume of air from a large opening, but the air from a small 
opening loses its velocity when it strikes a solid body, just the 
same as the air from a large opening. When the blast from a 
small tuyere strikes the solid fuel in front of it, its velocity 
is gone and it will not penetrate any further into the stock 
than the same volume of blast from a large tuyere. It is not 
the velocity at which the blast passes into a cupola that drives 
it to the center, but the force behind the blast. Neither is it 
the velocity of the blast that does the melting. It is the vol- 
ume of blast. It therefore follows that nothing is gained in 
melting by forcing the blast through a small tuyere into a 
cupola with great velocity, and much is lost by increasing the 
power required to run the blower to force the blast through 
a small tuyere. 

The small tuyere was one of the greatest mistakes made in 
the old-fashioned stave cupola. In these cupolas, many of 
which we have seen, only two tuyeres of 3 or 4 inches diameter 
were placed in a 30-inch cupola, and the improvement made in 
melting in the modern cupola is largely due to the enlarge- 
ment of the tuyeres and the free admission of blast to the 
cupola. 

The combined tuyere area of a cupola should be equal to 
three times the area of the outlet of the blower when the 
blower is of a proper size for the cupola. These dimensions 

4 



50 THE CUPOLA FURNACE, 

may seem large at first sight, but it must be remembered that 
the size or area of a tuyere when a cupola is not in blast does 
not represent the area of the tuyere when a cupola is in blast 
or the volume of blast that may be admitted to the cupola by 
the tuyere. When a cupola is in blast the space in front of 
the tuyere is filled with fuel weighted down by tons of iron. 
This fuel closes the mouth of the tuyere, and the outlet is rep- 
resented by the number of crevices between the pieces of fuel 
through which the blast may escape. Should a large piece of 
fuel fall in front of a tuyere the blast cannot remove it and the 
tuyere may be closed and rendered useless. Small tuyeres 
are more liable to be closed in this way than large ones, 
and for this reason they should never be placed in a cupola. 
Small tuyeres, furthermore, are not only more liable to be 
stopped off by the fuel but also tend to promote bridging by 
admitting an insufilicient amount of blast at certain points. 

HEIGHT OF TUYERE. 

There is a wide difference of opinion among foundrymen as 
to the height or distance tuyeres should be placed in a cupola 
above the sand bottom. So great is this difference of opinion 
at the present time that tuyeres are placed in cupolas at from 
2 inches to 5 feet above the sand bottom. This wide variation 
in the height of tuyeres is due to some extent to the different 
classes of work done in different foundries, it being claimed by 
foundrymen making heavy work that it is necessary to have 
the tuyeres high to hold molten iron in the cupola and keep it 
hot for a large casting. Foundrymen making light castings 
requiring very hot iron draw the iron as fast as melted, and do 
not think it necessary to have high tuyeres to hold iron in the 
cupola. In the many experiments we have made in melting 
iron in a cupola, we have placed the tuyeres at various distances 
above the sand bottom, and closely observed the effect of 
tuyeres at different heights. We learned by these experiments 
that the fuel under the tuyeres is not consumed in melting, 
nor is it wasted away to any extent by the heat or molten iron 



CUPOLA TUYERES. 5 I 

coming in contact with it. Charcoal may be placed in the 
bottom of a cupola, and if care is taken to prevent it being 
consumed by admission of air through the front before the 
blast is put on, the charcoal will not be consumed during the 
heat and may be found in the dump. We have tried this in our 
experiments to soften hard iron by bringing the molten metal 
in contact with charcoal in the bottom of a cupola, and found 
it correct. Pieces of charred wood used in lighting up are 
often found in the dump after having remained in the cupola 
through a heat. If these soft combustible substances are not 
consumed under the tuyeres, then it is not at all likely that the 
less combustible hard coal and coke are consumed. No iron 
can be melted in a cupola under the tuyeres, and the only 
function of the fuel below the tuyeres is to support the stock 
in a cupola above the tuyeres. If there is not sufificient heat 
in the bottom of a cupola to consume wood or charcoal, then 
there is not sufficient heat to keep molten iron hot for any 
length of time; and it is a well-known fact among practical 
foundrymen that large bodies of molten iron can be kept hot 
and fluid for a greater length of time in a ladle w^hen covered 
with charcoal to exclude the air than it can be in a cupola. 

Another reason given in favor of high tuyeres is that it is 
necessary to have them high to tap slag in long heats. The 
only slag in a cupola that can be drawn through a slag hole is 
a light fluid slag that floats on top of the molten iron or rests 
on the bottom of the cupola when there is no molten iron in 
it, and this slag may be drawn at any point between the sand 
bottom and tuyeres. When a slag hole is placed high, slag 
only can be drawn when the cupola is permitted to fill up with 
molten iron and raise the slag upon its surface to the slag hole. 
Slag may then be drawn for a few minutes while the cupola is 
filling up with iron to the slag hole. As soon as the iron 
reaches the slag hole, however, it flows out and must be tapped 
from the front. The slag then falls in the cupola with the sur- 
face of the iron as it is drawn off and the slag hole must be 
closed to prevent the escape of blast through it. Iron tapped 



52 THE CUPOLA FURNACE. 

after permitting a cupola to fill up to a high slag hole is always 
dull. 

When a slag hole is placed low it is not necessary to have 
the cupola fill up with iron before slag can be tapped, for the 
slag may be drawn off the bottom of the cupola, and, further- 
more, the slag hole may be opened and permitted to remain 
open throughout a heat without waste of blast. The flow of slag 
regulates itself when the hole is of proper size. It is, there- 
fore, not necessary to place tuyeres high that slag may be 
drawn from a cupola, nor is it necesssary to hold iron in a 
cupola for a large casting or to keep it hot. Molten iron 
should be handled in a ladle and not in a cupola. 

Hot iron for light work cannot be made in cupolas with high 
tuyeres, and for this reason the tuyeres in stove foundry cupo- 
las are always placed low. In cupolas of large diameter, hav- 
ing a large bottom surface for molten iron, the tuyeres are 
placed so low that those at the back of the cupola are not 
more than i inch above the sand bottom, and those in front 
not more than 2 ox 2}4. inches above the sand bottom. 
Tuyeres placed in this way give ample space below them to 
hold molten iron for this kind of work, for the iron must be 
very hot and is drawn from the cupola as fast as melted, and 
the cupola is large enough to melt iron as fast as it can be 
handled, and it is only when the cupola is not working free 
that it is stopped up to accummulate iron. The tuyeres in any 
cupola may be placed as low as in these large ones, if provision 
is made for handling the iron as fast as melted. 

In smaller cupolas not capable of melting iron sufficiently 
fast to fill a 40 pound hand-ladle, every 8 or 10 seconds the 
tuyeres are placed from 2 to 4 inches above the sand bottom, 
so that a sufficient quantity of iron may be collected before 
tapping to give each man in the section catching a hand-ladle 
full, and fill the ladle in about 6 seconds. 

In cupolas of very small diameter the tuyeres should be 
placed from 6 to 10 inches above the sand bottom. These very 
small cupolas melt so slow that if the iron is drawn as fast as 



CUPOLA TUYERES. 53 

melted the stream is so small that the iron is chilled in flowing 
from the cupola to the ladle more than it is by holding if in the 
cupola until a body of iron is collected sufficient to supply a 
large stream. 

In machine and jobbing foundry cupolas tuyeres are gen- 
erally placed from i8 to 24 inches above the sand bottom. 
The object in placing the tuyeres so high is to hold iron in the 
cupola for a large casting. But, as before explained, this is not 
necessary or advisable. Another reason for these high tuyeres 
is that they are necessary for tapping slag. The slag from 
many cupolas is drawn off at the tap hole with the iron, and a 
number of spouts have been invented for separating the slag 
from the iron and preventing it running into the ladle. Slag 
may be drawn from the back of a cupola on a level with the 
sand bottom at that point, if the iron is drawn as fast as melted, 
or it may be drawn i, 2 or more inches above the sand bottom 
at that point. It is, therefore, not necessary to place tuyeres 
at so great a height to tap slag. 

The tuyeres in cupolas for heavy work should be placed 
from 6 to 8 inches above the sand bottom when slag is not to 
be tapped. This gives an abundance of room in a cupola for 
holding iron while removing or placing a large ladle, and that 
is all that is necessary. The tuyeres in many of the cupolas 
used in Bessemer steel works are placed 5 feet above the 
bottom. They are probably placed at so great a height because 
the tuyeres in the first cupola constructed for this work were 
placed at that height. Tuyeres in all cupolas should be placed 
as low as they can be for the size of the cupola and facilities 
for handling the iron, for the fuel placed in a cupola under the 
tuyeres is not consumed in melting and is wasted by being 
heated in the cupola and crushed and burned in the dump. 
The value of fuel wasted every year in the United States by 
the use of high tuyeres in cupolas is sufficient to make a man 
rich. 



54 THE CUPOLA FURNACE. 

NUMBER OF TUYERES. 

A cupola may be supplied with blast from one tuyere placed 
on one side of the cupola, but the objection to one tuyere ar- 
ranged in this way is that the heat is driven by the blast 
against the opposite side of the cupola, and the destruction of 
lining at this point is very great. For this reason, at least two 
tuyeres are always placed in a cupola, and they are located on 
opposite sides so that the blast will meet in the center and be 
diffused through the stock. When a greater number of tuyeres 
than two are placed in a cupola they are located opposite each 
other and at equal distances apart, to admit an equal amount of 
blast on all sides and prevent an uneven destruction of lining 
from the heat being forced unevenly against it by the blast. 
Any number of tuyeres desired may be placed in a cupola, 
and as high as lOO have been used in a 40-inch cupola, and a 
greater number in larger cupolas. But these large numbers 
have given no better results in melting than two or four tuyeres 
in the same cupolas. It is not necessary to place a large num- 
ber of small tuyeres in a cupola to distribute the blast evenly 
to the bed, and it is not advisable to put in small tuyeres, which 
are easily closed by the fuel, cinder and iron, and are oftener 
rendered useless than large ones. Better results are obtained 
from large tuyeres and fewer of them. 

The largest cupola in use may be supplied with blast by two 
tuyeres if they are big enough. The large cupola of the 
Buffalo School Furniture Company, Buffalo, N. Y., is supplied 
with blast by two tuyeres 12x18 inches, placed on opposite 
sides. This cupola, which is 60 inches in diameter inside, 
does excellent melting with only these two tuyeres, and the de- 
struction of lining in melting is very light. We saw a large 
cupola with two tuyeres of about the above dimensions in use 
in a stove foundry in St. Louis, Mo., about 20 years ago, and it 
did excellent melting. The results obtained from these two 
cupolas would go to show that there is nothing gained in dis- 
tributing the blast to the bed evenly by a large number of 
small tuyeres. When a number of tuyeres are placed in one 



CUPOLA TUYERES. 55 

row, every other tuyere is sometimes placed about the width of 
the tuyeres higher than the tuyeres on either side of it. We 
have, however, never observed that anything was gained in 
melting by placing tuyeres in this way. When a double row 
of tuyeres is used the upper row should be made very small in 
comparison with the lower row, for if they are made of the 
same size as the lower one, or even half the size, and the two 
rows are placed at any great distance apart, the heat is so con- 
centrated upon the lining between them that it may be burned 
out to the casing in one or two heats. Foundrymen using the 
double tuyeres, who find the destruction of lining very great, 
may prevent it to some extent by reducing the size of the 
upper tuyeres. 

SHAPE OF TUYERES. 

The shape of a tuyere has nothing to do with the melting, 
except as it may tend to prevent bridging or increase the depth 
of the melting zone by supplying blast to the fuel at different 
heights in a cupola. A small horizontal slot tuyere extending 
around a cupola, or the greater part of the way around it, 
tends to promote bridging, and it is generally conceded that a 
cupola with a tuyere of this kind cannot be run for a greater 
length of time than two hours without bridging and clogging 
up. Vertical slot and reducing tuyeres supply blast to the bed 
at different levels and increase the depth of the melting zone 
the same as the double tuyere. For this purpose the Trues- 
dale, Lawrence and triangular tuyere, with elongated sides, are 
excellent when made of a proper size and placed a proper 
distance apart. When it is not desired to admit the blast 
to the bed at different levels, the flat or oval tuyeres are 
generally considered the best shapes, for they admit the blast 
freely, and a less amount of fuel is required for a bed with these 
shapes than with a round or square tuyere of the same area. 

TUYERES TO IMPROVE THE QUALITY OF IRON. 

All kinds of fancy-shaped tuyeres have been placed in 
cupolas to improve or change the quality of iron in melting. 



56 THE CUPOLA FURNACE. 

They have been placed to point up, point down, point across 
each other at certain angles, and to point to the center of the 
cupola. There is nothing more absurd than to attempt to im- 
prove the quality of iron in a cupola by the shape or angle of 
the tuyeres. The instant the blast leaves the mouth of a 
tuyere it strikes the fuel in front of it. The shape or angle 
given to it by the tuyere is then instantly changed, and it 
passes through the crevices in the fuel until its oxygen enters 
into combination with the carbon of the fuel and produces 
combustion. It then escapes at the top of the melting zone, 
where it comes in contact with the iron as carbonic acid gas. 
This is the result, no matter what the shape or angle of the 
tuyeres, if a proper amount of blast is supplied. It may be 
claimed that the blast acts upon the iron as it drops through 
the fuel in the bed after being melted ; but as before stated, the 
shape or angle given to the blast by the tuyeres is changed by 
the fuel, and the efTect on the iron of the blast from one tuyere 
would be the same as from another. 

TUYERE BOXES. 

The tuyeres may be and are often formed in the lining of a 
cupola when laying the brick, but this is a very poor way of 
making tuyeres, for there is nothing to support the brick and 
maintain the shape of the tuyeres, and they are often broken 
or burned away until there is no regular shape to the aper- 
ture, and it is difficult to put the blast into the cupola at the 
point desired or to prevent iron or slag getting into the tuyere. 
Tuyeres are more generally formed with a cast iron lining or 
tuyere box, having the shape and size of tuyere desired. This 
box may be cast with a flange on one end and be bolted to the 
casing, or it may be cast without a flange and placed in the 
lining at the desired point as it is laid up. The boxes are made 
in both ways, but it is better to cast it with a flange and bolt them 
to the casing, making an air-tight joint, as it then insures the blast 
going directly into the cupola at the point desired. Tuyere 
boxes laid in a lining answer the purpose very well when the 



CUPOIA TUYERES. 5/ 

lining is new, but when it becomes old and shaky, or a section 
is removed and replaced, the lining often settles and the grout- 
ing or filling falls out, leaving crevices through which the blast 
escapes between the casing and lining, and from there enters 
the cupola at points where it does no good. 

The cold blast supplied to a cupola keeps the tuyere box 
cool, and it is not necessary to cast it hollow and fill it with 
water to prevent it being melted or injured by the heat. The 
only part of the box that is exposed and liable to be injured 
is the end next the fire, and to protect it the box at this point 
is generally cast about ^ inch shorter than the thickness of the 
lining and the end covered with a little clay or daubing. 



CHAPTER IV. 

CUPOLA MANAGEMENT. 

The peculiarities in the working of every cupola must be 
learned before it can be run successfully, and this can only 
be done by working it in different ways. It is a question 
very much disputed whether a cupola constructed upon the 
latest improved or patented design is superior to one of the old 
style. This question can only be decided by the intelligent 
working of each cupola, and the advantage will always be found 
in favor of the one that is properly worked, no matter what its 
construction. It is the duty of every foundryman to give his 
personal attention to the working of his cupola if he has time. 
If he is not a practical founder or has not the time to devote to 
this branch of the business that it requires, then he should 
have his foundry foreman give it his personal attention for a 
sufficient length of time each day to see that everything is right 
in and about the cupola. 

No cupola can be run successfully by any given rule or set 
of rules, for conditions arise to which the rules do not apply. 
We shall therefore not only give directions for the proper work- 
ing of a cupola at every point, but shall also give the results or 
effect of bad working at every point, so that the founder when 
he finds his cupola is not operating well may have some data 
from which to draw conclusions and be able to overcome the 
difficulty. 

DRYING THE LINING. 

The cupola having been newly lined, nothing is to be done 
to the lining for the first heat but to dry it. A very high or 
prolonged heat is not required for this when only one thick- 
ness of brick is put in and laid up in thin grout. The lining 

(58) 



'CUPOLA MANAGEMENT. 59 

may be dried by making a wood fire after the sand bottom is 
put in, or by starting the fire for the heat a Httle sooner than 
usual. But the fire must not be started too early or the bed 
will be burned too much and the cupola filled with ashes, 
which will retard the melting. 

When a backing or filling of wet clay or sand several inches 
thick is put in between the casing and lining, more time and 
care are required in drying. It must then be dried slowly and 
evenly, or the filling will crack, and when jarred in chipping 
out will crumble and work out through cracks in the lining or 
holes in the casing and leave cavities behind the lining. 
When a lining is put in in this way, the doors are put up and 
covered with sand and a good coal or coke fire is made in the 
cupola and allowed to remain in over night. In the morning the 
bottom is dropped to remove the ashes and cool off the lining 
before making up the sand bottom for a heat, 

PUTTING UP THE DOORS. 

The first thing to be done when making up the cupola for a 
heat is to put up the bottom doors. When the cupola is of 
small diameter and the door light it may be raised into place 
and supported by one man. But when the door is heavy two 
men are required, and if the cupola is a large one and the door 
made in two parts, three men are required to lift and support 
them. Two men get inside the cupola and raise one-half into 
place while the third man supports it with a temporary prop ; 
they then raise the other half as far as it can be raised with 
their bodies between the two doors, where it is supported by a 
temporary prop. The men then get under the door on their 
hands and knees and raise it into place on their backs, and it is 
then supported by a prop. 

Numerous devices have been arranged for raising the doors 
into place, but they soon get out of order from the heat of the 
dump or carelessness in manipulation, and they have almost all 
been abandoned. When the cupola is very small and the door 
light, it is sometimes supported by an iron bolt attached to the 



60 THE CUPOLA FURNACE. 

under side of the bottom plate at the front, where it can be 
readily withdrawn with an iron hook to drop the bottom. But 
the doors are generally supported by a stout iron prop or post 
placed under the door near the edge opposite the hinges. 
Double doors are supported by a stout iron prop in the center 
and generally a light one at each end of the doors to prevent 
them springing when charging the fuel and iron, or by a sud- 
den settling of the stock, as may occur when melting large 
chunks. A great many melters have no permanent foundation 
under the cupola upon which to place the main prop, but make 
one every heat by laying down a small plate upon the sand and 
setting the prop upon it. The plate is often placed too high 
or too low, making the prop too long or too short, and the 
plate must be raised by putting a little more sand under it or 
lowered by scraping away a little sand. While this is being 
done the heavy iron prop, which frequently requires two men 
to handle in the cramped position in which they are placed 
under the cupola, has often to be put up and taken down two 
or three times before it is gotten into the right position to 
support the doors. 

All this extra labor can be avoided and time saved by im- 
bedding a heavy cast iron block in the fioor or foundation 
under the cupola for the prop to rest upon. It must extend 
down a sufificient distance to insure its not being disturbed 
when shoveling out the dump. A block 6 inches square and 
lO inches long, placed with the end level with the floor, will 
seldom be displaced, and makes a sure foundation for the prop. 
The size of prop required to support a bottom depends upon 
the size of cupola. In small cupolas the stock is supported to 
a large extent by pressure against the lining, while in large 
cupolas the stock is supported almost entirely by the prop. 
For small cupolas the props are made from i ^ to 2 inches 
diameter, and for large cupolas from 3 to 3^ inches diameter. 

The props for large cupolas not only have a greater weight 
to support, but they are seldom pulled out of the dump and 
are therefore, if light, liable to be bent and twisted to such an 



CUPOLA MANAGEMENT. 6 1 

extent as to render them useless. For this reason they are 
often made heavier than is actually necessary for the support 
of the bottom. Quite a number of foundrymen have adopted 
the plan of attaching a ring to the prop near the top or bottom 
with which to draw it from the dump and avoid heating it. The 
ring is made large and hangs loosely, or as a long loop which 
stands out from the prop. When the prop is to be removed a 
hook is placed in the ring or loop and a quick jerk given, 
which releases it, and it is at once drawn from under the 
cupola. 

Some of the older melters never use the iron prop, but 
measure and cut a new wood prop for their cupola every heat. 
Many of them are so superstitious that they think the cupola 
would not melt without the new prop, and they would rather 
give up their job than try it. Such melters are not so plentiful 
now as they were 20 years ago, when we first began traveling as 
a melter through this country and Canada, but we find when 
visiting foundries there are still a few of them left. 

DROPPING THE DOORS. 

When it is desired to drop the doors it is done by removing 
the props or drawing the bolt. The small props are first taken 
out, being released by a stroke of the hammer, and are care- 
fully laid away so that they will not be bent by the heat of the 
dump. A long bar with a handle on one end and a large hook 
on the other is then placed under the cupola with the hook be- 
hind the main prop and about 10 or 12 inches from it. By a 
sudden jerk of the bar the hook is made to strike the bottom 
of the prop a sufficiently hard blow to knock it out of place 
and permit the door or doors to drop. Two or more blows of 
the bar are sometimes necessary to release the prop, but it can 
always be released in this way. The prop can also be released 
by striking it at the top with a straight bar, but it is oftener 
missed than hit, and many thrusts are sometimes required to 
bring it down. Bolts are only used on small cupolas from 
which the dump falls slowly, and the bolt can generally be with- 



62 THE CUPOLA FURNACE. 

drawn by a blow of the hammer without danger to the melter. 
If it cannot be withdrawn in this way without danger of burn- 
ing the meher, a hook is made on the end of the bolt or a ring 
placed in it so that it may be drawn with a hooked bar or 
struck with a long straight bar. 

SAND BOITOM. 

When the door or doors are in place and properly sup- 
ported, any openings or holes that may have been burned 
through them are carefully covered with a thin plate of iron, 
and all cracks through which the bottom sand might escape 
when dry are closed with clay. The doors are then covered 
with a bed of sand several inches in thickness, which is known 
as the sand bottom. The sand employed for this purpose 
must not be of a quality that will burn away and permit the 
molten iron to get down to the doors, or melt and form a hard 
mass that will not fall from the cupola when the doors are 
dropped, neither must it be so friable as to permit the molten 
iron to run through it when dry. 

The clay sands when used for a bottom burn into a hard, 
tough mass that adheres to the lining all around the cupola, 
and in a small cupola frequently remains inplace after the door 
is dropped and has to be dug out with a bar before the cupola 
can be dumped. Parting sand, sharp and fire sands are very 
friable and difficult to keep in place. They do not resist the 
action of the molten iron well, but melt and form a slag. 
Mixtures of clay and. sharp sand burn too hard and do not drop 
well. The loam sands are the only ones suitable for a sand 
bottom, and sand that has been burned to a limited extent 
makes a better bottom than new sand. 

In stove and other foundries with large gangway floors the 
scrapings from the gangways are collected in front of the 
cupola, passed through a No. 2 riddle to recover the scrap 
iron, and the sand used for the cupola bottom. This sand 
makes the very best kind of bottom. It is clean and free from 
cinder, soft and pliable, packs close, resists the action of the 



CUPOLA MANAGEMENT. 6$ 

molten iron and drops free. In foundries where the daily- 
gangway cleanings are not sufficient to make the bottom, part 
of the old bottom is used over and the gangway cleanings are 
mixed with it or placed on top. In foundries where there are 
no regular gangways to clean every day, the heavy part of the 
dump is thrown out and the sand bottom passed through a No. 
2 riddle and used over again. When the bottom sand is used 
over day after day it must not be riddled out too close, and a 
little fresh material must be added to it each day to prevent it 
becoming rotten from repeated burnings and containing too 
many small particles of cinder, which render it fusible and 
easily cut away by the molten iron. The cleanings from the 
molding floors are generally added or a few shovels from the 
sand heaps, and in case it becomes too rotten a few shovels of 
new molding sand are mixed with it. 

When the material contains so much cinder that it does not 
make a smooth bottom, a few shovels of burned sand from the 
heaps are put on top to give an even surface and prevent the 
molten iron coming in contact with the cinder and cutting 
the bottom. The bottom sand is generally wet with water, but 
some melters wet it with clay wash, to make it more adhesive 
and give it more strength tp resist the action of the molten 
iron. A thick clay wash gives strength to a rotten sand when 
mixed with it, but it also increases the tendency of the bottom 
to cake and hang up, and it is better to improve the bottom 
material in the way above described and wet it with water 
only. The sand when wet is cut over and evenly tempered, 
and should be no wetter than molding sand when tempered for 
a mold. 

The sand may be thrown into the cupola through the front 
opening, or may be thrown in at the charging door, but it is 
generally thrown in at the front, for it is more convenient to 
the material, and is also convenient for spreading it in the 
cupola. When the cupola is small the melter stands by the 
side of it and makes up the bottom by passing his arm in 
through the front opening, but when the cupola is large he 



64 THE CUPOLA FURNACE. 

goes inside, and his helper shovels the sand in as he wants it. 
The first sand thrown in is carefully packed around the edges 
with the hands to insure a tight joint. As the balance of the 
sand is thrown in it is spread evenly over the bottom in layers 
from I to 2 inches thick, and each layer is evenly rammed or 
trampled down until the required thickness of bottom is 
obtained, which is from 3 to 6 inches, according to the rise of 
the cupola. The desired pitch or slope for throwing the iron 
to the front is then given, and the bottom butted evenly and 
smoothly all over. The melter next goes carefully around the 
edges with his hands and feels for any soft spots there may be 
near the lining, and slightly raises the edges of the bottom 
around the lining to throw the iron off and prevent it working 
its way down between the lining and sand bottom. The 
bottom is then carefully brushed and smoothed off, and in 
small cupolas a bucket of thin clay wash is sometimes thrown 
in at the front and caught in the bucket as it runs out. This is 
called slushing the bottom, and is done to give a smooth, hard 
surface. 

The sand bottom does not always remain impervious to the 
molten metal, but is sometimes penetrated or cut up and de- 
stroyed by it, in which case a leakage of molten iron takes 
place from the bottom of the cupola that is difftcult to stop. 
Leakage of this kind may be due to springing of the bottom 
doors when charging and the cracking or loosening of the sand 
bottom around the lining. This can be prevented by placing 
more props under the doors to support them. Sand that has 
been used over and over in a bottom until it has become worn 
out and filled with cinder is readily cut up and converted into 
a slag by the molten iron, and it is only a question of the time 
occupied in running ofif the heat whether the bottom gives 
way or stands. When the bottom sand gets into this condi- 
tion, it must be renewed by the addition of new sand, or the 
bottom covered with a layer of sand from the molders' sand 
heaps. 

Molten iron will not He upon a wet, hard substance, but will 



CUPOLA MANAGEMENT. 65 

explode or boil and cut up the material upon which it is 
placed. If the bottom sand is made too wet, or rammed too 
hard, or rammed unevenly, the iron will not lie upon it, but 
will boil and cut up the sand until it gets down to the doors, 
which it will melt and run through. When a bottom cuts 
through, melters frequently attribute it to the bottom being too 
soft ; and we have seen Ihem take a heavy pounder and ram a 
bottom as hard as a stone. In these cases, if the sand was 
worked very dry, or the bottom was well dried out before any 
molten iron came in contact with it, it did not cut up or leak; 
but if the sand was wet when the molten iron came down, boil- 
ing at once took place and the bottom soon cut through — and 
in such cases they generally cut through about every other 
day. In the sand bottom of a cupola we have the same 
elements to contend with, so far as molten iron is concerned, as 
we have in a mold ; and the sand should be worked no wetter, 
rammed no harder, and rammed as evenly as the sand for a 
mold. The sand should not be worked wet for a bottom, under 
the impression that it is dried out before the iron comes down, 
for the ashes of the shavings, wood, coal or coke cover the 
bottom soon after the fire is started, and protect it from the 
heat to such an extent that it is only dried to a very limited 
degree before the iron comes down upon it. Water may be 
seen dripping from a very wet bottom long after the blast is 
on. Even if it were dried out, wet sand cracks when dried 
rapidly and should not be used. We shall not attempt to give 
any directions for stopping a leak after it occurs, for the time 
and place to stop a leak is when putting in the sand bottom ; 
and if all the remedies we have given for preventing leaks fail, 
then it is time to change the melter. 

The pitch or slope given to the bottom to cause the molten 
iron to flow to the tap hole from all parts of the bottom has a 
great deal to do with the temperature of the iron and nice 
working of a cupola. When the bottom is made too low and 
flat, molten iron lies in the bottom of the cupola and becomes 
dull. As the melted iron falls into this iron drop by drop, it is 

5 



66 THE CUPOLA FURNACE. 

instantly chilled and the iron when drawn from the cupola 
is dull. This efifect is more marked in a cupola melting very 
slowly, and a low bottom may be the cause of very dull iron 
when a sufficient quantity of fuel is consumed to make ver}'- 
hot iron. A high pitch throws the iron from the tap hole with 
great force and spouting velocity, and it is almost impossible to 
run a continuous stream from a cupola with such a bottom. 
It is more difficult to keep the tap hole and spout in order, and 
the stream must be closely watched to prevent it shooting over 
the ladle and burning the men. Slag flows freely from the tap 
hole with the stream of iron when the bottom has a high pitch, 
even when there is very little slag in the cupola. But the flow 
of slag from the tap hole with the iron may be entirely stopped 
by changing the pitch of the bottom, no matter how great the 
quantity of slag in the cupola. The action of the iron at the 
spout is entirely changed by the pitch of the bottom. A hard 
iron may be made to run smooth from the spout, while a soft 
iron may be made to sparkle and fly, giving all the indications 
of a hard iron. The best expert on the quality of iron at the 
spout may be deceived in the iron by the pitch of the bottom, 
and it is only in the extremely hard and extremely soft iron 
they cannot be deceived. The bottom should never be made 
hollow in the center and high all around the outside with an 
outlet or trough to the spout. This concentrates the iron in 
the center in such a way that a few hundred weight places as 
great a pressure upon the front as a ton would do if the 
bottom were flat, and the front may therefore be forced out by 
a comparatively small body of iron. The instant the tap hole 
is open the iron rushes out with great force, and it is almost 
impossible to stop it as long as there is any molten iron in the 
cupola. 

The bottom should be made flat and level from side to side 
with only a slight rise around the lining, which should not ex- 
tend out more than i or 2 inches from the lining. The pitch 
from back to front should not be more than ^ to ^ inch to 
the foot. This has been found to be a sufficient slope to throw 



CUPOLA MANAGEMENT. 6^ 

all the iron to the front in an ordinary cupola. But in cupolas 
that melt very slowly a little more slope may be given, so as to 
concentrate the iron more rapidly and prevent it chilling on 
the bottom. 

In cupolas with two tap holes the bottom must be sloped so 
that all the melted iron in the cupola can be drawn from either 
tap hole. It is very difficult for a melter to see what slope he 
is giving a bottom when inside the cupola, and for this reason 
many of them seldom get the slope alike. The melter should 
be provided with a notched stick or some other gauge, for 
measuring down from the top or bottom of each tuyere, to 
serve as a guide in sloping the bottom, so that it may be given 
the proper pitch and put in alike every heat. 

SPOUT. 

The old way of making a cupola spout is to place a short 
piece of pig iron on the bottom plate on each side of the front, 
and build up a spout between them with clay or loam. The 
modern spouts are made of cast iron with a flat or eight-square 
bottom, and are from 4 to 6 inches deep, 7 to 10 inches wide 
and I to 10 feet long. They are given a fall from the cupola 
of about I inch to the lineal foot, and are lined with a refractory 
material to protect them from the molten iron. The spout 
lining is made of a different material from the sand bottom, and 
generally consists of molding sand, loam or a mixture of fire 
clay and sharp sand. Some of the molding sands make an 
excellent spout lining that is not cut or fused by the stream of 
molten iron, while others crumble and break up too readily 
when cleaning the spout of dross and dirt, and cannot be used 
for this purpose. When a molding sand can be used it makes 
a nice clean spout that is easily and quickly made up. It is 
readily dried, and when making up the spout the crust of the 
old lining can be removed with a bar, and the sand wet up and 
used over with a coating of sand without removing it from the 
spout. For long spouts, requiring a good deal of material to 
line them, molding sand is the most economical lining that can 
be used. 



68 THE CUPOLA FURNACE. 

Some of the loam and blue clays make excellent spout 
linings alone or when mixed with sand, and are the only 
materials used for this purpose in some sections of the country 
where they can be procured at a moderate cost. They make 
a stronger lining than molding sand — that is, not so liable to be 
broken up when cleaning the spout of dross and slag — and, 
furthermore, they dry quickly. The lining material probably 
more extensively used than any other is a mixture of fire clay 
and sharp sand. These two refractory substances when com- 
bined in right proportions and thoroughly mixed make one of 
the very best spout linings. But when not properly mixed 
they make one of the poorest linings. 

When too much clay is used the lining does not give up the 
water of combination until heated to a very high heat, and it is 
almost impossible to get the lining dry so that the iron will not 
boil in the spout the first few taps when the spout is long, or 
sputter and fly when it is short. It cracks when dried rapidly, 
and is melted into a tough slag that bungs up the spout and 
cannot be removed without destroying the lining. When too 
much sand is used the lining crumbles when touched with the 
bar and is cut and melted by the stream. When the clay and 
sand are not thoroughly mixed the lining crumbles and cuts or 
melts in spots. A spout lining made of these two materials 
in right proportions, properly mixed and dried, becomes as 
refractory as a fire-brick, and 50 or 100 tons of iron may be 
run from a spout lined with them without a break in the lining. 
There are a number of other materials used for spout linings 
that are only found in certain localities, and their use is re- 
stricted to the districts where they can be procured at a 
moderate cost. But those above described are the materials 
most commonly used for this purpose. 

The spout lining is made up new every heat, and when 
putting it in the spout is wet to make it adhere to it. The 
sand bottom is cut away from the front and the spout lining 
made to extend into the cupola past the tap hole. A perfect 
joint is made between the sand bottom and spout lining, and a 



CUPOLA MANAGEMENT. 69 

little clay wash is generally brushed over the joint to make it 
more perfect and prevent cutting. Care must be taken to not 
get the bottom of the spout at the tap hole higher than the 
sand bottom, and also to give it the same pitch as the sand 
bottom. The bottom is put in first and is made about t inch 
thick when the spout has been given the proper pitch. If the 
spout has not been given a proper pitch, the lining is made 
heavier at the end next the cupola and light at the outer end 
and the pitch given in the lining. This is the common practice 
in short spouts. 

The sides of the lining are built up full at the bottom, so as 
to leave only a narrow groove in the middle and keep the 
stream always in one place, but are sloped back from the 
middle to the top of the spout to give a broad spout surface 
for carrying the stream of iron. A half round groove i inch 
deep and 2 inches wide at the top is sufficient to carry off the 
stream of iron from almost any cupola. But the spout is liable 
to be choked up by dirt from the tap hole or slag, and it is 
made large for safety. A rammer is seldom used in making up 
a spout and it is generally made up with the hands and one of 
the bod sticks, or the small round stick used to make the tap 
hole. 

When molding sand is used it is worked a little wetter than 
for molding and is beaten down with the bod stick and shaped 
up with the hands and bod stick. When clay or a mixture of 
clay and sand is used, it is worked wet and placed in the spout 
in balls and beaten or pressed into shape with the hands, and 
the bod stick is used to true it up and form the groove in the 
middle, Short spouts are made up with but little difficulty, 
but great care must be taken in making up a long spout to 
have it perfectly true and properly pitched, so that it will clean 
itself of molten iron the moment the cupola is stopped in. 

The greatest strain upon the' spout lining is under and 
around the tap hole, where it is liable to be cut away by the 
pressure and current of the stream or to be melted if the 
material is not very refractory, and it may be broken up by 



70 THE CUPOLA FURNACE. 

the tap bar if not very tenacious when heated to a high tem- 
perature. When molding sand or other materials that do not 
stand a high temperature well or are not very tenacious when 
heated are used, a layer of fire clay and sharp sand is placed 
over the lining material under the tap hole. When the heat is 
very heavy and a large amount of iron is drawn from one tap 
hole, a split fire brick is embedded under the tap hole to pre- 
vent cutting and insure a good tap hole throughout the heat. 
The spout is seldom coated or painted with blacking after it is 
made up or dried, but when a friable material is used for lining 
it is sometimes coated with clay wash. 

If the spout is made with a broad, flat bottom the stream 
takes a new course every time the cupola is tapped, and before 
the heat is over the spout is so bunged up that the iron collects 
in pools. A continuous stream cannot, therefore, be main- 
tained the length of the spout, and two or more streams may 
fall from the end of the spout at the same time. To prevent 
this, shape the lining to form a small groove for the stream in 
the center and keep it there every tap. The quality of the 
lining material has a great deal to do with the condition of a 
spout during the running out of a heat. The spout may be 
cut out in holes by the stream and pools of iron form in the 
spout at every tap. This is due to the lining material crumb- 
ling and being washed away by the stream. When this does 
not occur every heat with the same material, it is due to the 
material not being properly mixed ; but if it does occur every 
heat, it is due to poor material. The spout may become 
choked or bunged up with slag when no slag flows from the 
tap hole with the iron. This is due to the lining melting and 
forming a slag. It is very difficult to keep a spout in order 
through a long heat when this occurs, and the lining material 
should at once be changed. Slag should be removed from the 
spout when very hot by lifting it up with a bar, or chipped 
away with a sharp bar when quite cold. All attempts to 
remove a tough semi-fluid slag break up and destroy the lining. 



CUPOLA MANAGEMENT. 7 I 

FRONT. 

The front opening of the modern drop botton cupola is 
made so small that it is not necessary to place an apron or 
breast plate over it to hold the front or breast in place, as is 
done with the draw front cupola. The material used for put- 
ting in the front is generally the same as is used in making up 
the spout. The front is generally put in after the fire has 
burned up, but some melters put in the front before lighting, 
and light from the tuyeres. Others make up the tap hole and 
half the front with a stiff mixture of fire clay and sharp sand 
before lighting up, and fill in the other half after the fire has 
burned up. But as a general rule the entire front is left open 
to give draft for lighting, and the front is put in after the fire is 
burned up and about ready for charging. This gives sufficient 
time for drying it before the blast is put on. 

When about to put in the front the ashes and dust are care- 
fully brushed from the spout where the front is to be made> 
and the spout and front opening are wet all around with water 
or clay wash to make the front material adhere and insure a 
good joint. A breast of small pieces of coke is built in front 
of the fire, or a small board cut to fit the front, with a notch in 
the bottom for the tap hole, is placed in front of the fire to pre- 
vent the front material from being rammed or pressed too far 
back into the cupola. A small iron bar or a round wooden stick 
is then laid in the bottom of the spout to form the tap hole. 

If the front is made of molding sand or other material that is 
likely to crumble at the tap hole and be cut away by the 
stream of iron or be broken away by the tap bar, a little fire 
clay and sharp sand, or other refractory material, is placed 
around the bar or stick to form the tap hole. The front 
material of molding sand or loam is then thrown in and 
rammed solid against the board, sides, top and bottom of the 
opening. If the front is made of clay or sand, and worked 
wet, it is made into balls and pressed into place with the 
hands. When the opening has been filled the front is cut 
away downward and inward from the top and sides of the 



72 THE CUPOLA FURNACE. 

opening to the bar forming the tap hole, until the tap hole is 
not more than i ^ inches long. The surplus material from the 
front is then removed from the spout, the bar drawn from tap 
hole and the front and spout carefully trimmed up. 

If the spout lining and front have been made up with clay 
and sand, or other wet material, a wood fire is built on the 
spout to dry it and the front. When the spout and front are 
made up with molding sand or loam they are generally dried 
by the flame from the tap hole before stopping in, and an iron 
plate is sometimes laid on top of the spout to concentrate the 
heat upon it. 

The front is generally made the full thickness of the lining 
and cannot be forced out by the pressure of molten iron if 
properly put in. When the front material is worked too wet, it 
falls away from the opening at the top when drying, and the 
opening must be closed to prevent the escape of the blast. If 
the tap hole is made too long the iron may chill in it, and the 
cupola cannot be tapped without cutting a new hole. This 
makes very bad work, for the iron is generally melted from the 
old tap hole by the stream passing through the new one, and 
the two holes become one. It is then very difificult to stop in 
or control the flow of iron. 

When the front material is poor it melts into a semi-fluid 
slag that settles down and closes up the tap hole with a tough 
adherent slag that is difhcult to remove. When this occurs 
the tap hole can only be kept open by continually opening it 
up with a tap bar. The only way to overcome this difficulty 
is to use a more refractory front material. Mineral fluxes 
sometimes make a front material fusible that is not otherwise 
fusible. When trouble is experienced in keeping the tap hole 
open when using a flux, or after one flux has been substituted 
for another, the composition of the front material must be 
changed or another material used. 

When no board is used and the front material is rammed 
back into the fire until it becomes solid in the front, the front 
is ragged and soft on the inside and melts and makes a bad 



CUPOLA MANAGEMENT. 73 

tap hole even when the material is good. A good front or 
spout Hning can always be made from fire clay and sharp sand 
by mixing them in right proportions for the purpose for which 
they are to be used. 

SIZES OF TAP HOLE. 

The sizes the tap hole is made depends upon how the iron is 
to be drawn from the cupola. If it is desired to run a continu- 
ous stream from the cupola, the tap hole is made small to suit 
the melting capacity of the cupola. If it is desired to accumu- 
late a large body of iron in the cupola and fill a large ladle 
rapidly when the cupola is tapped, the hole is made large. 
The tap holes are made of various sizes from ^ inch to i y^ 
inches diameter, to suit the different kinds of work. When it 
is desired to run a continuous stream it is very desirable that 
the tap hole should not be cut and enlarged by the stream. 
This is generally prevented by placing a very refractory 
material around the rod forming the tap hole. But some 
melters have a form in which they mold a tap hole from a care- 
fully prepared material that will not cut and dry it in an oven 
or on a stove. This tap hole form, when thoroughly dried, is 
placed in position on a split fire-brick and the front made up 
around it, which always insures a regular sized hole throughout 
the heat. 

LOCATING THE TAP HOLES. 

We have already described the manner of putting in the front 
and forming the tap hole, and shall here only consider the loca- 
tion and number of tap holes. The tap hole is placed in the 
side of the cupola from which it is most convenient to convey 
the iron to the work to be poured, and it makes no difYerence in 
the working of the cupola upon which side it is placed if the , 
bottom is sloped to throw the iron to the hole. One tap hole 
is sufficient to run the iron from any ordinary cupola, but two are 
frequently put in. In some cupolas two fronts and tap holes 
are put in side by side only a few inches apart, and two spouts 
are made up so that the tap hole can be kept in better order 



74 THE CUPOLA FURNACE. 

for drawing off the iron. They are tapped turn about, and in 
case too great a quantity of melted iron accumulates in the 
cupola they are both opened at one time. Two tap holes 
placed in this way can only be worked for hand ladle work at 
the same time, and they cannot be worked to advantage even 
for that, for they are so close together the men are in each 
other's way. One tap hole if properly made and managed 
will run ofT all the iron a cupola will melt, and it is poor cupola 
practice to put in two fronts and tap holes in this way. 

Two tap holes are frequently placed in a cupola for con- 
venience in carrying the iron from the cupola to the molding 
floors. They are generally placed on opposite sides of the 
cupola, to save carrying the iron around the cupola or from 
one molding room to another. Two tap holes are also placed 
in cupolas to facilitate the removal of the iron in hand ladles. 
Six 40-pound hand ladles are all that can be safely taken from 
a spout per minute. When more than this number of ladles 
are filled and removed per minute, the men have to move so 
rapidly there is danger of a clashing of ladles and spilling of 
iron, and when a heavy stream once gets away from the men 
and falls to the floor, it spatters and flies so that it is difBcult 
to stop in or again catch it. When more than 8 tons are 
melted per hour in a cupola for hand ladle work, two tap holes 
are always put in. They are placed in the side of the cupola 
that is nearest the work to be poured, but always at a sufificient 
distance apart to admit of the men-catching at one spout being 
out of the way of those catching at the other. 

SLAG HOLE. 

A slag hole for drawing off slag is sometimes placed in a 
cupola, but it is not used except when the cupola is run be- 
yond the capacity to which it can be run successfully without 
slagging. The hole is placed below the level of the tuyeres, 
and when it is desired to accumulate a large body of molten 
iron in a cupola the slag hole is placed high. When the iron 
is drawn from a cupola as fast as melted the hole is placed low. 



CUPOLA MANAGEMENT. 75 

The opening through the casing and Hning is generally made 
oval and about 3x4x5 inches. 

The slag hole front when the hole is placed high consists of a 
plug of the same material used for the tap hole front. The 
plug is placed in the outer end of the opening and is from 2 to 
3 inches thick. A hole 1 inch diameter is made through it for 
a tap hole, and the plug or front is cut away from the edges of 
the casing to the hole until the hole is not more than i]4, 
inches long. When the hole is placed low and the slag per- 
mitted to flow throughout the heat after it is opened the plug is 
made of loam or molding sand mixed with a little blacking to 
make it porous when heated, and the plug is placed in the hole 
on the inside flush with the lining. No tap hole is made 
through the plug when placed in this way, and when it is 
desired to tap slag a hole is cut through it with a sharp pointed 
tap bar. This material does not bake hard, and the entire 
plug may be cut out when necessary. 

Slag chills more rapidly in a tap hole than iron, and is more 
difificult to tap or draw from a cupola, and when the slag hole 
is not properly arranged it cannot be drawn at all. If the tap 
hole is made small and long the slag chills in the hole and it is 
difficult to open the hole or keep it open. When the lining is 
very thick it must be cut away and the hole made large inside 
of the front, or the slag will chill in the lining the same as it 
might in the hole in the front. The hole in the lining can be 
made 6 or 8 inches diameter without injuring the lining, and a 
hole of this size will admit a sufficient quantity of slag to the 
tap hole to prevent it chilling. There is never any difficulty 
from the slag chilling when the front and tap hole are placed 
flush with the inside of the lining, for the slag is kept hot and 
fluid in the cupola, and may be drawn off whenever there is a 
sufficient quantity in the cupola to flow from it. It is therefore 
better to cut away the casing and lining, and place the front 
flush with the inside of the lining. 



"J^ THE CUPOLA FURNACE. 

LIGHTING UP. 

When the cupola is small the shavings are thrown in from 
the charging door and evenly distributed over the bottom. 
The wood is cut short and split fine and dropped down, a few- 
pieces at a time, and so placed that the fire will burn up evenly 
and quickly. When the cupola is large the melter goes down 
into it and his helper passes him down the shavings and wood 
from the charging door. The shavings are evenly spread over 
the bottom, care being taken to get plenty around the outside 
to insure a good light. A layer of fine, light dry wood is then 
laid over the shavings, and on this a layer of heavier wood, 
and so on until the required quantity of wood for lighting the 
bed is placed in the cupola. Care is taken to arrange the 
wood so that it will burn up evenly and quickly. A light dry 
wood should be used, and the pieces must not be very large or 
too much time will be consumed in burning them, and the bed 
will settle unevenly. 

When the wood has been arranged the melter gets out and a 
thin layer of small coal or coke is placed over the wood. The 
bed fuel is then thrown in evenly over the wood. All the bed 
is put in but a few shovelfuls, which are kept to fill up any 
holes that may be formed by an uneven settling. The charg- 
ing door is then closed and the shavings lighted at the front 
opening. The tuyere doors are opened to give draft and the 
fire left to burn up. When the wood is nearly burned out and 
there is a good fire of hot coals at the front and tuyeres, the 
melter generally puts in the frontspout and builds a wood fire 
on the spout to dry them. He then looks in at the charging 
door, and if the smoke is burned off and the fire beginning to 
show through the top of the bed, he puts in the remaining 
few shovels of fuel and makes the top of the bed as level as 
possible. He then closes all the tuyere doors but one and 
begins charging the iron into the cupola. 

Straw may be used in place of shavings for lighting up when 
shavings cannot be procured. The wood should be dry pine 
or other light wood, and it must not be used in too large sticks 



CUPOLA MANAGEMENT. 'J'J 

or the bed will be burned too much before 'the wood is burned 
out ; and if the iron is charged before the wood is burned out, 
it smokes and the melter cannot see how to place the iron or 
fuel. For the same reason, hard or green wood should not be 
used in lighting up. 

When the bed burns up on one side and not on the other in 
a small cupola, the bed may be burned up on the other side 
after the blast is put on and the heat run ofif successfully. But 
when the bed burns up on one side and not on the other in a 
large cupola the bottom had better be dropped at once. We 
once had to drop the bottom of a 6o-inch cupola before the 
heat was half ofif, for the reason that the melter was careless in 
arranging the wood and lighting up, and charged the iron with 
the bed only burned up on one side. He thought the blast 
would make it burn up on the other side, but it did not, and 
the heat was a failure. Never burn the bed up to warm or 
heat up the cupola, for a cupola does not require to be heated 
before it is charged, and the lining burns out fast enough with- 
out wasting fuel to burn it out. 

THE BED. 

Iron is melted in a cupola within a limited space, known as 
the melting point or melting zone. The melting point is the 
highest point in a cupola at which iron is melted properly, and 
the melting zone is the space between the highest and lowest 
point at which iron melts properly. Iron may be melted to a 
limited extent above or below these two points, but it is 
burned, hardened and generally dull. The melting zone ex- 
tends across the cupola above the tuyeres, and is from 6 to 8 
inches in depth. Its exact location is determined by the 
volume of blast and the nature of the fuel employed in melt- 
ing. A large volume of blast gives a high melting point, and 
a small volume a low melting point. A soft, combustible fuel 
gives a high melting point, and a hard fuel a low melting point, 
the blast being equal in volume with both fuels. 

To do good melting the melting point must be discovered. 



78 THE CUPOLA FURNACE. 

and only a sufficient quantity of fuel placed in the bed to bring 
the top of the bed up to the melting point. When the fuel is 
hard anthracite coal, the rule is to use a sufficient quantity of 
coal in the bed to bring the top of the bed 14 inches above the 
top of the tuyeres when the wood is burned out; with hard 
Connellsville coke 18 inches, and with soft coke 20 to 25 
inches. But the melting point is varied by the volume of blast 
and these rules do not always hold good. So the melting 
point in each cupola must be learned to get the best results 
from the cupola. 

To find the melting point a bed is put in according to the 
rule and iron charged upon it. If the iron is a long time in 
coming down after the blast is put on, or the iron melts very 
slowly during the melting of the first charge, but melts faster 
at the latter end of the charge and is hot, the bed is too high 
and the iron is being melted upon the upper edge of the melt- 
ing zone. Fuel and time are then being wasted, and the fuel 
should be reduced so as to place the iron at the melting point 
when melting begins. If the iron comes down quick but is 
dull, or if it comes slow and dull and does not grow hotter at 
the latter end of the charge, the melting is being done on the 
lower edge of the melting zone and the quantity of fuel should 
be increased to bring the top of the bed up to the melting 
point. When the top of the bed is placed only half way up 
the melting zone the iron comes down hot and fast, but the 
bed does not melt the quantity of iron it should and the latter 
part of the charge on the bed is dull. The latter part of the 
charge on the bed when the bed is the proper height is also 
dull if the charge is too heavy for the bed, and care must be 
taken in noting this point. 

If by comparison with the charges of iron in various sized 
cupolas the charge on the bed is found to be light, the bed 
should be raised until the melting indicates that it is at a 
proper height; then the weight of iron on the bed may be in- 
creased, if the charge is too light. When raising or lowering 
a bed, it should be done gradually by increasing or decreasing 



CUPOLA MANAGEMENT. 79 

the fuel from 50 to 100 pounds each heat until the exact 
amount of fuel required in the bed is found. If the changes in 
the bed are made gradually in this way, the effect of the changes 
upon the melting may be observed more accurately and better 
results obtained than when a radical change is made by in- 
creasing or decreasing the fuel in large amounts at one heat. 
When the amount of fuel is found that brings the top of the 
bed to a height that gives the best results in melting, the top 
of the bed is maintained at that point each heat. 

When a cupola is newly lined the diameter is decreased from 
what it was with the old lining, and the weight of fuel in the 
bed must be decreased to bring the top of the bed down to 
the melting point, and as the lining burns out and the cupola 
gets larger the fuel must be increased to keep the bed up to 
the melting point. Trouble is often experienced in melting 
after a cupola has been newly lined. This is because the 
diameter of the cupola is reduced from 6 to 10 inches, and 
the bed and charges are not changed to correspond with the 
reduced size of the cupola. There is never any trouble of this 
kind in foundries where a cupola book is provided and a record 
kept of the melting from one year's end to another, for the 
melter or foreman can look back and see the weight of the bed 
and charges when the cupola was newly lined, and the increase 
made in the weight as the lining burned out and the diameter 
increased. 

No definite or even approximate weight can be given of the 
amount of fuel required for a bed in cupolas of dififerent 
diameters, for the tuyeres are placed at such a variety of 
heights above the sand bottom that for two cupolas of exactly 
the same diameter twice the quantity of fuel may be required 
for a bed in one as is required for a bed in the other. Cupolas 
with two or three rows of tuyeres require a larger amount of 
fuel for a bed than cupolas with but one row, but the same gen- 
eral directions for burning and managing the bed apply to all 
cupolas. 



80 THE CUPOLA FURNACE. 

CHARGING. 

The old way and the way still in vogue in some localities of 
stocking, loading or putting the fuel and iron into a cupola is 
to place a sufficient quantity of fuel in a cupola to fill it above 
the tuyeres. On this fuel or bed are placed from 50 to 500 
pounds of iron, according to the size of the cupola, then from 
one to four shovels of fuel are put in and from 50 to 200 
pounds of iron, and so on until all the iron to be melted is 
placed in the cupola. 

This way of stocking a cupola mixes the fuel and iron in the 
cupola and they come down to the melting point together. 
The fuel fills a space that should be filled with iron, and a 
great deal of the melting surface of the cupola is lost, and the 
cupola's melting capacity reduced in proportion. 

The modern way of stocking a cupola is to put in the fuel 
and iron in layers or charges. Each layer or charge of fuel is 
separated from the layer or charge above and below it by a 
layer or charge of iron, and each layer of iron is separated by 
a layer of fuel. This way of stocking a cupola is known as 
charging the cupola. When a cupola is charged in this way 
the iron comes down to the melting point in a body extending 
over the melting surface of the cupola, and the entire melting 
surface is utilized. The melting capacity of a cupola is about 
one-half greater when charged in this way than when the fuel 
and iron are mixed, and the consumption of fuel is also less. 

The first charge of iron is placed on the bed at the melting 
point. In melting this charge of iron a certain amount of fuel 
is consumed and the top of the bed settles down from the top 
of the melting zone to the bottom of the melting zone. The 
charge of fuel on top of the charge of iron that has just been 
melted settles with the iron until it unites with the bed and 
places the top of the bed again at the top of the melting zone, 
ready to melt the next charge of iron, and so on with each 
succeeding charge of fuel and iron throughout the heat. This is 
the correct theory of melting iron in a cupola, and the practice 
that must be followed to obtain the best results from a cupola. 



CUPOLA MANAGEMENT. 8 1 

Now, having described the theory of charging and melting, 
let us consider the practical working of a cupola upon the 
theory. The amount of iron placed upon the bed in the first 
charge and in each charge through the heat must be the exact 
amount of iron the fuel will melt while settling from the melt- 
ing point to the bottom of the melting zone. The amount of 
fuel in each charge must be the exact amount required to raise 
the bed from the bottom of the melting zone to the melting 
point. If the charges of iron are made too heavy the iron 
comes dull at the latter end of the charge and hot at the first of 
the charge until a few charges have been melted, when it comes 
dull all through to the end of the heat. When the charges of 
iron are too light the iron comes hot, but there is a stoppage 
in melting at the end of each charge, changing to continuous 
but very slow melting as the heat progresses. 

When the charges of fuel are too heavy the iron melts slowly 
and unevenly, and if the heat is a long one it comes dull and is 
hardened in melting. When the charges of fuel are too light 
and the charges of iron heavy the result is dull iron. When 
the charges of fuel and iron are both too light the iron gener- 
ally comes hot but slowly throughout the heat, and the full 
melting capacity of the cupola cannot be realized. 

There is no rule for making the weight of the first charge of 
iron of any definite proportion to the weight of the bed of 
either anthracite coal or coke that holds good in all cupolas. 
Manufacturers of some of the patent cupolas have such a rule 
for their cupolas that is approximately correct, but the tuyeres 
in dififerent sizes of these cupolas are always placed at the 
same height and about the same amount of fuel is required for 
a bed. The bed will melt a heavier charge of iron in settling 
than the other charges of fuel, and the first charge is generally 
made from one-third to one-half heavier than the subsequent 
charges. The weight of the first charge of iron varies from 
two and one- half to four and one-half times the weight of the 
bed with anthracite coal ; with coke the weight of the first 
charge varids from one and one-half to four and one-half times 
the weight of the bed. 
6 



82 THE CUPOLA FURNACE. 

These wide variations in the weight of the first charge of 
iron in proportion to the weight of the bed are largely due to 
the difference in the height of tuyeres and the large amount of 
fuel required for a bed in a cupola with very high tuyeres. 
But variation is also due in many cases to bad judgment in 
estimating the weight the first charge should be. The greater 
the weight of the first charge in proportion to the weight of 
the bed, the better the average will be in melting, and careful 
experiments should be made with every cupola to learn the 
largest amount of iron it will melt on the bed with safety, and 
that amount should always be placed in the first charge. 

There is no rule for making the weight of the charges of fuel 
or iron of any definite proportion to the weight of the bed or 
first charge of iron, and the weight of the charges of both fuel 
and iron is frequently changed in different parts of the heat, 
to give a hotter iron for some special work or to make the iron 
run of an even temperature through the heat. In practice, the 
weight of the charges of iron to the charges of anthracite coal 
varies from 6 to 14 pounds of iron to the pound of coal. With 
coke they vary from 6 to 15 pounds of iron to the pound of 
coke. These variations in the per cent, of iron to fuel are due 
in many cases to the quality of fuel and in many other cases to 
poor judgment in working the cupola. In all cases the charge 
of iron should be made as heavy as the charge of fuel will melt 
and produce good hot iron for the work, for this is the only 
way a good per cent, of iron to the pound of fuel can be 
obtained. 

PLACING THE CHARGES. 

The top of the bed is made as level as it can be before 
charging the iron, and the smoke must all have disappeared 
so the melter can see how to place the charges. When the 
cupola is very high a few hundred of stove plate or other light 
scrap is placed upon the bed to prevent the heavy pieces of 
pig or other iron breaking up the fuel and settling down into 
the bed when thrown in. The pig should be broken into short 
pieces and placed in the cupola with the end toward the lining. 



CUPOLA MANAGEMENT. 83 

The pieces of pig or other iron are placed close together so as 
to utilize all the heat and prevent its escape up the stack, and 
each charge is made as level as it can be on top. The gates 
and cupola scrap are placed on top of the pig and are used to 
fill up holes and level up the charge. Old scrap is generally 
charged with the pig when heavy, and on top of the gates 
when light. Rattle barrel iron and gangway scrap or riddlings 
go in with the gates, a few few shovels to each charge. 

The charge of fuel is distributed evenly over the charge of 
iron, and the second charge of iron is put in the same as the 
first, and the second charge of fuel the same as the first, and 
so on until the cupola is filled to the charging door. Charg- 
ing is then stopped and the door closed until the blast goes on. 
When melting begins the stock begins to settle, and the door 
is opened and charging continued as before until all the iron to 
be melted is placed in the cupola. While charging is going 
on the cupola is kept filled to the charging door to prevent the 
gas igniting and making a hot flame at the charging door, 
which makes it hot for the men and difificult to place the 
charges of fuel and iron properly. When charging is finished 
the charging door is closed to prevent sparks or pieces of 
burning fuel being thrown upon the scafifold. 

When the iron is all or nearly all melted that has been 
charged, and it is discovered there is not sufficient iron in the 
cupola to pour off the work, more iron is sometimes charged. 
At this stage of the heat the stock is so low in the cupola and 
the heat is so intense that the cupola is in a very bad condi- 
tion for resuming charging to melt more iron. It is only a 
waste of fuel to charge it into the cupola at this stage of the 
heat, and the only iron that can be melted on the fuel already 
in the cupola is light scrap, and but a limited quantity of it. 
When the charging door is opened the heat at the opening is 
so intense that the men cannot go near it, and the scrap must 
be thrown in from a distance or by standing alongside of the 
cupola out of the heat and throwing the iron around into the 
door on a shovel. 



84 THE CUPOLA FURNACE. 

Poor melting may be due to bad charging. Iron or fuel 
should never be dumped into a cupola from a barrow, for it all 
falls on one side of the cupola. The iron generally lays where 
it falls in a pile, and the fuel rolls to the other side of the 
cupola, and good melting cannot be done with the fuel on one 
side and the iron on the other. This way of charging is about 
equal to the old way of mixing the fuel and iron, and only 
about one-half of the melting capacity of the cupola can be 
realized. Fuel should never be emptied into a cupola from a 
basket or box, for it all falls in one place and cannot be spread 
evenly over the charge of iron. To charge a cupola properly 
the iron must all be thrown in with the hands, and the fuel with 
a shovel or fork. 

CHARGING FLUX. 

When it is desired to tap slag, the slag-producing material or 
flux is charged in the cupola on top of the iron and evenly dis- 
tributed. The flux is sometimes put on each charge of iron, 
but generally about one-sixth of the heat is charged without 
flux. After that, flux is put in on every charge of iron except 
the last one or two charges, where it is not required if the 
proper amount has been used through the heat. The quantity 
of flux required depends upon the slag-producing propensity 
of the material used and the condition of the iron charged, and 
is from 30 to 100 pounds to the ton of iron melted. If the 
iron to be melted is all clean iron, the amount of flux required 
is less than when the iron is dirty scrap or a large per cent, of 
the heat is sprues and gates that have not been milled and are 
melted with a heavy coating of sand on. 

If it is not desired to tap slag and the flux is used only to 
make a brittle slag in the cupola, it is charged in small quanti- 
ties of from 5 to 10 pounds to the ton of iron, and is placed 
around the outside of the charge near the lining. Flux is 
sometimes charged in a cupola in a sufficient quantity to pro- 
duce a large body of slag through which to filter the molten 
iron and cleanse it of impurities, but not in a sufficient quantity 
to admit of slag being drawn from the cupola. This way of 



CUPOLA MANAGEMENT. 85 

fluxing works very well in a short heat, but in a long heat the 
slag sometimes absorbs a large amount of impurities, becomes 
overheated and boils up in the cupola and fills the tuyeres, 
and when boiling the slag cannot be drawn from the cupola at 
the slag hole and the bottom generally has to be dropped. 

BLAST. 

Before the blast is put on the tuyere doors are all tightly 
closed and luted to prevent the escape of any of the blast dur- 
ing the heat, and they should be examined from time to time 
to see that the luting has not blown out and the blast is not escap- 
ing. The blower is speeded up to the full speed at once, and the 
full volume of blast given the cupola from the start. The old 
way of putting on the blast light and increasing or decreas- 
ing it at different stages of the heat has been abandoned 
by practical foundrymen, and the cupola is given the same 
blast from the begining to the end of the heat. This is the 
only way good melting can be done in a cupola charged in the 
manner before described. If the cupola does not work properly, 
remedy the evil by changing the charges, but never vary the 
blast in different parts of a heat to improve the melting. 

When the blast is first put on, it is indicated by a rush of 
blast from the tap hole and at the charging door by a volume 
of dust passing up the stack. Then follows a bluish colored 
gas which bursts into a bluish flame as the stock settles, chang- 
ing to a yellowish hot flame as the stock sinks still lower. If 
the stock is kept up level with the charging door in a cupola 
of good height the gas does not ignite, and it is the aim of the 
chargers to keep the stock up to this point until they are 
through charging. When the blast is shut ofif from a cupola 
for any cause or at the end of the heat before the bottom is 
dropped, one or more of the tuyere doors are at once opened 
to prevent gas from the cupola passing into the blast pipe, 
where it is liable to explode and destroy the pipe. 

The full consideration of the blast for a cupola would take up 
more space than we care here to give to it and would lead our 



86 THE CUPOLA FURNACE. 

readers too far from the subject of working a cupola. We shall 
therefore leave it for fuller consideration under another heading. 

MELTING. 

Melting begins in a cupola soon after the blast is put on, 
and the exact length of time is indicated by the appearance of 
molten iron at the tap hole. When the iron is charged two or 
three hours before the blast goes on, and the bed is not too 
high, iron flows from the tap hole in from three to six minutes 
after the blast is on. When the iron is charged and the blast 
is put on, immediately iron appears at the tap hole in from 1 5 to 
20 minutes, after the cupola is filled if the bed is not too high. 
When the bed is too high, iron melts when the surplus fuel is 
burned up and permits it to come down to the melting point, 
and it is very uncertain when melting will begin ; and it is gen- 
erally from half an hour to an hour before any molten iron 
appears at the tap hole. If iron does appear at the tap hole 
within 15 or 20 minutes after the blast is on, the bed is either 
too high or the fire has not been properly lit, and the bed is 
not doing its work efficiently. 

Foundrymen differ as to the time for charging the iron before 
the blast is put on. Some claim that fuel is wasted by lighting 
the fire early and charging the iron two or three hours before 
the blast is put on, while others claim fuel and power are only 
wasted by putting on the blast as soon as the iron is charged. 
We have melted iron in both ways, and we prefer to charge the 
iron from two to three hours before the blast is on, except 
when the cupola has a very strong draft that cannot be shut 
off, as is sometimes the case when there is no slide in the blast 
pipe for shutting off the blast, and as air is supplied to the 
cupola through the pipe. When iron is charged and the 
cupola filled to the charging door with fuel and iron, and 
the draft shut off from the cupola, the cumbustion of fuel in 
the bed is very light and the heat that rises from it is utilized 
in heating the first charge of iron. When the blast is put on, 
this charge of iron is ready to melt and iron comes down in a 



CUPOLA MANAGEMENT. 8/ 

few minutes. When the blast is put on immediately after the 
cupola is charged the iron is cold, and time is required to heat 
it before it will melt, and the blower must be run 15 or 20 
minutes before iron appears at the tap hole, and the first charge 
melts more slowly than when the iron has been heated before 
the blast is put on. 

We think the best way is to put on the blast about two hours 
after the charging begins. When the blast goes on, the tap 
hole is open and is left open until the iron melts and runs hot 
and fluid from it. From 10 to 20 pounds are generally per- 
mitted to run from the spout to the floor to warm the spout 
and insure the iron being sufficiently hot not to chill in the tap 
hole after stopping in. The first iron melted is always chilled 
and hardened to some extent by the dampness of the sand bot- 
tom and spout, and when the work is light and poured with 
hand- ladles, a small tap of a few ladles is made in a few min- 
utes after stopping in, and the iron used for warming the ladles 
and it is then poured into the pig bed or some chunks. In 
some foundries the cupola is not stopped in at all after the iron 
comes down. The first iron is used to warm the ladles, and as 
soon as the iron is hot enough for the work the molders begin 
pouring it. We recently ran off a heat of 31 tons in this way 
from a cupola for hand-ladle work without using a single bod 
for stopping in. 

When the iron is handled in large ladles a tap is not made 
until a sufficient quantity is melted to fill a ladle or there is 
a sufficient body of iron in the cupola to insure it not chilling 
in the bottom of a large ladle before another tap is made. 
When the blast blows out at the tap hole after a tap is made, 
it indicates that the melted iron is all out of the cupola or the 
tap hole is too large, and the cupola should be stopped in 
until iron collects in the bottom, or the size of the tap hole 
should be reduced to prevent the escape of the blast. The size 
of the tap hole is reduced when it becomes too large to run a 
continuous stream without blowing out, by stopping in with 
a hod of stiii" clay and sand that will not cut, and as soon 



55 THE CUPOLA FURNACE. 

as the bod is set, cutting a new tap hole through the bod with 
the tap bar. Iron should be melted hot and fast, and it 
should never be drawn from a cupola for any kind of foundry 
work if it is not hot and fluid enough to run stove plate or 
other light casi;ings. Iron is not burned in a cupola by melt- 
ing it hot and fast, but it is burned and hardened by melting 
it too high in the cupola and melting it slow and dull. 

Nothing is gained by holding molten iron in a cupola to 
keep it hot, for it can be kept as hot in a ladle as in a 
cupola, and iron should be drawn from a cupola as fast as 
melted or as fast as it can be handled in pouring the work. If 
we were running a foundry we should never stop in the cupola 
except to get enough iron to give a gang of men a hand-ladle 
full all round, or to remove a large-ladle from the spout. 
When the cupola is very small and melts slowly it is sometimes 
necessary to stop in and collect iron in the cupola, but it is not 
necessary to stop in a large cupola for this purpose. If the 
iron is all poured with hand-ladles the men should be divided 
into gangs, with only enough men in each gang to take away 
the iron as fast as melted. If this is not done and there is 
a large number of men, the ladles get so cold between catches 
that they chill the iron before it can be poured, and the melter 
is blamed for not making hot iron. 

The flow of iron from the tap hole indicates how the cupola 
is melting. If it has been properly charged the flow will be 
even in quantity and temperature throughout the heat, except 
in a very long heat, when the stream will get smaller and 
the cupola not melt so fast toward the end of the heat. When 
too much fuel is used the iron melts slowly and grows dull as 
the heat progresses. When the charges of iron are too heavy 
the iron is not of an even temperature throughout the heat, but is 
dull at the latter end of every charge and hot at the beginning 
of the next charge. When the charges of fuel are too heavy the 
iron melts very slowly at the beginning of each charge and fast 
at the latter end, and if the charges of iron are also too heavy 
the iron is dull at the latter end of the charge. If the cupola 



1 



CUPOLA MANAGEMENT. 89 

melts unevenly it is not being properly worked, and the mode 
of charging should be changed until it does melt evenly from 
the beginning to the end of the heat. 

POKING THE TUYERES. 

When the blast is first put on, the fuel in front of each tuyere 
is bright and hot, but it is soon chilled and blackened by the 
large volume of cold blast passing in, and the tuyere presents 
the appearance of being closed up and admitting no air to the 
cupola. The blast when first put on does not remove the fuel 
and make a large opening in front of each tuyere to get into 
the cupola, but works its way between the pieces of fuel in 
front of the tuyeres, and these openings remain open for the 
passage of blast after the fuel becomes cold and black. The 
blast, therefore, passes into the cupola just the same as when 
the fuel was hot, and it is not necessary to poke the tuyere 
with a bar or break away the cold fuel in front of each tuyere 
to let the blast into the cupola. 

Toward the end of a long heat, slag and cinder settle and 
chill at the bottom of a cupola, and often not only close off 
the blast at the tuyeres, but prevent it passing freely through 
the stock and out at the top. If the tuyeres are poked at this 
stage of the heat an opening may be made well into the stock. 
But in working the bar around in forming this opening most of 
the natural passages the blast has made for entering the stock 
are closed up. The new opening is only a hole bored into a 
tough slag or cinder from which there is no way for the blast 
to escape into the stock, and less blast enters a cupola after the 
tuyeres have been poked and opened up than entered before. 
The only time a tuyere should be poked with a bar is when 
cinder or slag has lodged or formed in front of it in such a way 
as to run a stream of molten iron into the tuyere. The tuyere 
door should then be opened and the slag or cinder broken 
away with a bar to prevent the iron running into the tuyere. 



90 THE CUPOLA FURNACE. 

FUEL. 

Theoretically ten pounds of iron are melted with i pound 
of anthracite coal, and 15 pounds with a pound of Connells- 
ville coke. But this melting is done in the foundry office or 
in the mind of the foreman, and it takes a little more fuel 
to melt iron in a cupola for foundry work. Six pounds of iron 
to I of anthracite coal and 8 pounds of iron to i of Connells- 
ville coke is by practical foundrymen considered good melting. 
A little better than this can be done in a full heat for the size 
of the cupola and under favorable circumstances, but in the 
majority of foundries fewer pounds of iron are melted to one 
of fuel than the above amount. 

It is sometimes necessary for the melter to put in a few extra 
shovelfuls of fuel when the bed has been burned too much before 
charging, or to level up the charges when two or three men are 
shoveling in fuel at the same time and get it uneven. The 
melter is generally blamed if the iron from any cause comes 
dull, and he will generally put in a few extra shovelfuls of fuel 
the next heat to make it hot, and if the iron does come hot the 
next heat the extra shovelfuls are put in every heat, but are not 
put on the cupola report. In this way foundrymen are often 
misled by the cupola report and suppose they are melting 
more pounds of iron to the pound of fuel than they really are. 
The only way the foundryman can know exactly how many 
pounds of iron he is melting to the pound of fuel is to have an 
accurate account kept of the amount of iron melted and com- 
pare it with the amount of fuel bought and delivered for the 
cupola, after deducting from it any amount that may have been 
consumed in stoves or core ovens. 

We recently met a foundryman who thought he was melting 
14 pounds of iron to the pound of fuel, but when he came to 
compare the iron melted with the fuel bought and delivered for 
the cupola he found he was only melting about 7 pounds of iron 
to the pound of fuel ; and about the same results would be 
found in every foundry that is claimed to be melting a very large 
per cent, of iron to fuel. There is nothing gained by saving a 



CUPOLA MANAGEMENT. 9 1 

few cents' worth of fuel in the cupola and losing a dollar's worth 
of work on the floor by dull iron, and there is nothing gained 
by using too great a quantity of fuel, for too much fuel in a 
cupola makes dull iron as well as too little fuel. 

Iron is not melted in a cupola for the fun of melting it or to 
learn how many pounds of iron can be melted with a pound of 
fuel, but is melted to make castings. What the foundryman 
wants from the cupola at the tap hole is an iron hot and fluid 
enough to make a sound casting, regardless of the amount of 
fuel required to produce it. As before stated, iron cannot be 
melted hot and fast in a cupola with either too much or too 
little fuel, and foundrymen have only to melt their iron as hot 
and fast as it can be melted in a cupola of the size they are 
using, to know that they are not using either too much or too 
little fuel in melting. 

If the foundryman will ask his neighbor what is the size of 
his cupola, how many tons does he melt per hour, how long 
does it take him to run off a heat, he will get a better guide to 
run his cupola by than if he asks him how many pounds of 
iron he melts to the pound of fuel. As soon as the founder 
undertakes to imitate his neighbor and do faster melting or get 
better results from his cupola, he will hear the old, old story 
from both melter and foreman : " We haven't enough blast." 
More cupolas have too much blast than too little, and the ap- 
parent deficiency of blast is due in the majority of cases to too 
much fuel in the cupola and the iron being melted only on the 
upper edge of the melting zone. It does not make any differ- 
ence how much or how little blast a cupola has. If it is given 
an even volume of blast throughout the heat, the cupola will 
melt a stream of iron of an even size and temperature through- 
out the heat except toward the end of a long heat, when the 
stream may get smaller. If the melter cannot run this kind of 
a stream from his cupola with an even blast, then he is at fault, 
and neither the blast, nor too much fuel, is the cause of the un- 
even melting. 

We have watched the charging of cupolas in a great many 



92 THE CUPOLA FURNACE. 

stove and machinery foundries, and as a rule more fuel is con- 
sumed in making dull iron in a machine foundry than is 
consumed in making hot iron in a stove foundry. This is simply 
because hot even iron cannot be produced with bad working of 
a cupola and too great a quantity of fuel, and the stove founder 
must liave his cupola properly worked or he cannot use the 
iron to pour the work. 

TAPPING BARS. 

Tapping bars are made of round iron of from ^ to i inch 
diameter, and are from 3 to lO feet long. The hand bars 
are made with an oval ring at one end to serve as a handle for 
rotating and withdrawing the bar when tapping. The other 
end is drawn down to a long sharp point for cutting away the 
bod and making the tap hole. The bars for sledging are made 
straight with a long sharp point at one end. This bar is only 
used in case the tap hole becomes so tightly closed that it cannot 
be opened with the hand bar, and seldom more than one is pro- 
vided for a cupola. From three to six hand bars are provided 
for each cupola, and when the ladles are all of the same size 
the tap bars are all made of the same size, except one or two 
small ones which are provided for clearing the hole of any slag 
or dirt that may be carried into it by the iron. 

When the iron is melted for different sized work and large 
and small ladles are used, the bars are of different sizes, so 
that a large or small hole may be made to suit the tap to be 
made or ladle to be filled. The bars are all straight except 
when the tapping is done from the side of a long spout. They 
are then slightly curved near the point, so that the hole can 
be made in a line with the spout. The bars are dressed and 
pointed at the forge before each heat, and are given any shape 
of point the melter may fancy. A square point cuts away a 
bod very rapidly when rotated and leaves a nice, clean hole, 
but is very difificult to keep a point square, for they generally 
become round after a few taps have been made and they come 
in contact with the molten iron a few times. For this reason 
they are generally made round at the forge. 



CUPOLA MANAGEMENT. 93 

Some melters have a short steel bar, with a sharp flat point, 
which they use for cutting away the bod before tapping, but 
never use it for opening the hole. This they do to remove the 
greater part of the bod from the spout before tapping, and pre- 
vent it getting into the ladles. A hammer and an anvil, or an 
iron block, should be placed near the cupola for straightening 
the points and breaking cinder or dross from the bars, and a 
rack should be provided within easy reach of the tap hole, 
in which to place the tap bars on end until wanted for use. 
There is nothing more slovenly and dangerous about a foundry 
than to have the tap bars lying around the floor when a 
heat is being run, and it is just as bad to set them up against a 
post from which they are all the time falling down. 

BOD STICKS. 

Two kinds of bod stick are used for stopping in a cupola; 
The wood stick and the combination wood and iron stick. 
The wood sticks are octagonal or round, from i ^ to 2 
inches diameter and from 5 to 10 feet long. They are made 
of both hard and soft wood and about an equal number of 
each wood, as some prefer one and some the other. When 
stopping in, the stick is held against the bod in the tap hole 
until it sets in the hole, and the stick generally takes fire from 
the heat of the spout. On this account they soon become 
small near the ends and have to be sawed ofT; for this reason 
they are always made longer than necessary and sometimes 
larger in diameter. 

The combination stick is of the same diameter as the wood 
stick, and from 4 to to feet long. An iron ring is placed 
on one end of the stick, and a rod of round iron of from ^ 
to ^ inch diameter and i to 3 feet long is placed in the end 
of the stick. On the end of the rod is placed a round button 
of from I ^ to 2 inches diameter, for carrying the bod. The 
object of the rod is to prevent the stick being burned by the 
heat of the spout every time the cupola is stopped in, and the 
length of the rod is made to correspond to the length of 



94 THE CUPOLA FURNACE. 

the spout. The ojection to the combination stick is that the 
button does not carry the bod as well as the wood stick, and 
the button and rod must be wet every time the stick is used to 
keep it cool, or the heat will dry out the bod and it will fall off. 
This repeated wetting rusts the buttom, and if the edges come 
in contact with the molten iron it makes the iron sparkle and 
fly ; and for this reason most founders prefer the wood sticks, 
even at the extra expense of keeping them up. 

An iron rod and button without the wood stick is also used 
in some foundries for stopping in, but they were not used by 
our grandfathers and are not popular with melters. Three or 
four bod sticks are provided for each cupola. They are placed 
on end in a rack alongside of the tap bars, within easy reach 
of the tap hole, and a bod is kept on each stick all the time 
the cupola is in blast. 

BOD MATERIAL. 

The bod is a plug used for closing the tap hole when it 
is desired to stop the flow of iron from a cupola, and the 
material of which the bod is composed has a great deal to do 
with the nice working of the tap hole. When the bod is 
composed of fire clay, or largely of fire clay, it does not 
give up the water of combination rapidly, and if a tap is 
quickly made after stopping in, the iron sputters and flies as it 
comes out of the hole. If the bod is permitted to become 
perfectly dry it bakes so hard that it cannot be cut away with 
the hand bar, and the heavy bar and sledge have to be used to 
make a hole of the proper size. If a friable sand is used it 
crumbles easily before the bar and a nice clean hole can be 
made ; but it does not hold well, and if the cupola is stopped 
in for any length of time the bod may be forced out by the 
pressure of metal. 

Some of the loams make an excellent bod that holds well 
and is easily cut away with the point of the bar, and leaves a 
clean hole. Some of the molding sands also make good 
bods in their native state, and there are several materials that 



CUPOLA MANAGEMENT. 95 

are peculiar to certain localities that make good bods. When 
a suitable material cannot be found it must be made by- 
mixing two or more materials. A good bod is made by mix- 
ing blue or yellow clay and molding sand. When these clays 
cannot be procured, a good bod can be made by mixing just 
enough fire clay with the molding sand to give it a little greater 
adhesive property, but not enough to make it bake hard. 
When a large body of iron is collected in the cupola before a 
tap is made, the bod material must be strong, and bake in the 
hole sufficiently hard to resist the pressure of the iron, and an 
entirely different material must be used for this kind of tapping 
than is used when the cupola is only stopped in for a few 
minutes at a time. 

Small cupolas from which only a small hand ladle is drawn 
before it is stopped in also require a different bod, for the hole 
has hardly time to clear itself before it is stopped in again, and 
if the bod burns hard or sticks in the hole, the hole is so hard 
to open that the small amount of iron is chilled by the bar 
and slow tapping before it can be run out. This kind of 
cupola requires a bod that will crumble and fall out as soon as 
touched, or burn out as soon as the hole is opened. A nice 
bod is made for this kind of work by mixing clay, molding 
sand and sawdust and makmg it fully half sawdust. Blacking 
or sea coal is also mixed with bod material to make it more 
porous when burned and crumble more readily when tapping. 

Horse manure was at one time considered to be one of the 
essentials of a good bod, but it has been replaced by blacking 
or sawdust, and is seldom used. A good bod should have 
strength to resist the pressure of molten iron in the cupola and 
at the same time break away freely before the iron and leave a 
clean hole. Such a material can be made suitable for any 
cupola, no matter how it is tapped, and a bod material should 
never be used that requires the sledging tap bar to open the 
tap hole. 



96 THE CUPOLA FURNACE. 

TAPPING AND STOPPING IN. 

When the blast is put on the tap hole is always open, and 
is left open until the iron melts and flows freely and hot from 
the hole. This is generally in from 5 to 20 minutes after the 
blast is on. While the melter is waiting for the iron, he 
arranges his tap bars, bod stuff and bod sticks, and places a 
bod on each stick to be ready for instant use. The bod 
material is worked a little wetter than molding sand to make 
it adhere to the end of the bod stick or button, but care must 
be taken not to have it too wet or it will make the iron fly 
when stopping in, and, furthermore, the bod does not hold well 
when too wet. The bod is made by taking a small handful of 
the bod stuff and pressing it firmly on the end of the stick 
with the hand. The size and shape the bod is made depend 
upon how the iron is tapped and the size of tap hole. When 
the hole is small and only stopped in for a few minutes at a 
time a small bod stick is used, and the bod made very small and 
shallow and only pressed into the hole a short distance, so that 
it can be quickly broken away when tapping. When the hole 
is large or has to be stopped in until a large body of iron 
collects in the cupola, the bod is made large, long and pointed, 
so that it may be pressed well back into the hole and stay in 
place until removed with the tap bar. 

The first iron melted flows from the hole in a small stream, 
and generally chills in the hole or spout and has to be removed 
with the tap bar ; but it soon comes hot enough to clear the 
hole, which is then closed, unless the first iron is used to warm 
the ladles and the hole is kept open through the heat. If the 
work is light, a small tap is made in a few minutes to remove 
any iron that has been chilled and dulled by the dampness in 
the sand bottom. But when the work is heavy this tap is not 
made and the molders go on with their regular pouring from 
the start. The tap is made by placing the point of the bar 
against the bod and giving it a half forward and back rotation 
and at the same time pressing it into the bod, or by carrying 
the handle end of the bar around in a small circle and at the 



CUPOLA MANAGEMENT. 97 

same time pressing it in. As soon as the bod is cut through, 
the bar is run into the hole once or twice and worked around a 
Httle to remove any of the bod that may be sticking round 
the sides of the hole. The bar must always be held in such a 
position as will make the hole in a line with the spout, or the 
stream will not flow smoothly and may shoot over the sides of 
the spout and burn the men catching in. 

When about to stop in, the bod is placed directly over 
the stream close to the tap hole and the other end of the stick 
is elevated at a sharp angle from the spout. The hole is 
closed by a quick downward and forward movement of the 
stick that forces the bod into the hole and checks the stream 
at once. The stick is then held against the bod for a few 
seconds until the force of the stream is stopped and the heat 
has set the bod fast in the hole. The part of the bod that does 
not enter the hole is then removed with the stick to keep the 
spout clean, and the stick is dipped in water to cool it, and 
another bod applied to be ready for the next time. There is a 
great knack in stopping in, that some melters never acquire. 
They hold the bod too far from the hole, and attempt to push 
it up, under or through the stream ; they get nervous and are 
not sure of their aim and strike the stream too soon, or the 
side of the hole, and the iron sputters and flies in all directions. 

The bod sticks are frequently made so long and slender or 
so heavy that it is impossible to accurately place the bod, and 
it is sometimes difificult to get the cupola stopped in with these 
long sticks. It is also difificult to stop in when the cupola is 
placed very high, for the melter cannot get up to place the 
bod stick at a proper angle for stopping in, and has to run 
the bod up through the stream, in place of cutting ofT the 
stream with the bod. An arm or bracket is sometimes placed 
over the spout near the tap hole, when long bars and sticks 
are used, upon which to rest the tap bars and bod sticks when 
tapping and stopping in. But a better plan is to construct a 
movable platform that can be placed alongside the spout for 
the melter to stand on. He can then use short bars and sticks, 
7 



98 THE CUPOLA FURNACE. 

and has much better control of the tap hole than with the long 
bars and sticks. 

At the tap hole is seen the skill of the melter in the results 
obtained from his labor. If the bed has been burned too much 
the first charge comes down fast and slack or dull. If the bed 
is too high the first iron is a long time in coming down. If too 
much fuel is used, the iron melts slowly and is dull toward the 
last if the heat is long. If the charges of iron are too heavy, 
the iron comes dull at the end of each charge. If the charges 
of fuel are too large, there is slow melting at the end of each 
charge. If the iron flows from the tap hole with great force 
and is difficult to control, the sand bottom has too much pitch. 
If slag flows freely from the tap hole with the iron, the hole 
is too large or the bottom has too much pitch. If the spout 
melts, crumbles or chips off, the material is poor or has not 
been properly mixed. If the tap hole cuts out, the material is 
poor or the tap hole has not been properly made. If the 
tap hole gums up and cannot be kept open, the front ma- 
terial is poor and is melted by the heat, and it may also be 
melted by the heat when it is good if rammed soft and ragged 
inside. If the tap hole cannot be opened without a sledge 
and bar, the bod bakes too hard and the material should be 
changed. If the bod does not hold, the material is not good 
or the bod is not put in right. If the cupola does not melt 
evenly throughout the heat and the same every heat, it is the 
fault of the melter and not of the cupola. 

DUMPING. 

As soon as the molders are through pouring their work, if 
there is no iron to be melted for other purposes, preparations 
are at once made for dumping the refuse from the cupola. 
The blast is first shut off by stopping the blower and the 
tuyere doors are at once opened to prevent the escape of gas 
from the cupola into the blast pipe, where it might do much 
harm. The melted iron in the cupola is then drawn off by the 
cupola men and poured in the pig bed. If there is a lot of 



CUPOLA MANAGEMENT. 99 

small iron in the cupola that has not been melted time is given 
it to melt to save picking it out of the dump, but if there is a 
lot of pig or other heavy iron unmelted it is let fall with the 
dump, and the bottom is dropped as soon as the melted iron is 
drawn off. 

The small props supporting the bottom are first removed 
and laid away. The main prop is then removed by striking it 
with a long bar at the top or pulling with a hooked bar at the 
bottom, and the instant it falls the doors drop. When the 
doors of a large cupola drop, the sand bottom and a greater 
part of the refuse of melting falls with them and a sheet of 
flame and dust instantly shoots out ten feet or more from the 
bottom of the cupola in all directions. But the flame disap- 
pears in an instant and the dust settles, revealing the white 
hot dump in a heap under the cupola. The cupola men then 
throw a few buckets of water on it to chill the surface and 
deaden the heat, and the melter puts a long bar into the 
tuyeres and tries to dislodge any refuse that may be hanging 
to the lining while it is hot. Small cupolas do not dump so 
freely, and the sand bottom has frequently to be started with a 
bar after the door drops. A long bar must be used for this 
purpose and the melter must be on his guard, for the dump may 
fall as free as from a large cupola the instant it is started and a 
sheet of flame shoots out. 

Small cupolas frequently bridge over above the tuyeres, and 
only the sand bottom and refuse below the bridge is dumped 
when the door falls. The aim of the melter is then to break 
away the bridge or get a hole through it, so that the cupola will 
cool off in time to be made ready for the next heat. He puts 
a bar in at the tuyeres and breaks away small pieces at a time, 
and if there is not a large body of refuse in the cupola, a few 
short pieces of pig are thrown in from the charging door, so 
that they will strike in the center and break through the bridge. 
This bridging and hanging up of the refuse in a cupola when 
only run for a few hours is entirely due to mismanagement, for 
any cupola, no matter how small it may be, can be run for six 



lOO THE CUPOLA FURNACE. 

or eight hours without bridging and be dumped clean if prop- 
erly worked. 

When the dump falls from a cupola it is a semi-fluid mass of 
iron, slag, cinder, dirt and fuel. This mass falls in a heap 
under the cupola, and if scattered or broken up when very hot 
it is more readily wet down and more easily removed when 
cold. In some foundries a heavy iron hook or frame is placed 
under the cupola before dumping and is withdrawn with a chain 
and windlass after the dump has fallen upon it and been par- 
tially cooled with water to harden it so that the hook will not 
slip through it without breaking it up and scattering it. In other 
foundries it is scattered with a long rake or hook worked by 
hand. In pipe foundries two or three short lengths of con- 
demned pipe are placed under the cupola before dumping, and 
the dump is broken up by running a bar into the pipe and lift- 
ing it up after the dump has been slightly cooled. But in 
a great many foundries where the dump is small or where there 
is plenty of room to remove it when cold it is let lie as it falls 
and is wet down by the cupola men, or a few buckets of water 
are thrown on by the cupola men to deaden it, and it is left for 
the watchman to wet down during the night. Care must be 
taken not to put on too much water, or the floor under the cupola 
will be made so wet that there will be danger of the dump ex- 
ploding when it falls upon it the next heat. 

REMOVING THE DUMP. 

A number of plans have been devised for removing the dump 
from under the cupola. Iron cars or trucks have been con- 
structed to run under the cupola and receive the dump as it 
falls, but they cannot be used unless there is sufficient room for 
the doors to swing clear of the car, and few cupolas are so con- 
structed. The dump must be removed from the car when hot 
to avoid heating and injuring the car, and considerable room is 
required for handling the car after it is taken from under the 
cupola. For these reasons cars are seldom used. Iron crates 
have been made to set under the cupola and receive the dump 



CUPOLA MANAGEMENT. 1 01 

and be swung out with the crane, but they get fast under the 
cupola and are soon broken, and it is almost as much work to 
handle the dump from the crate as it is from under the cupola. 
A number of other plans have been tried, but the dump must 
be picked over by hand, and it is as cheap to pick it over at 
the cupola and remove it in wheelbarrows as by any way that has 
yet been devised. The dump is broken up with sledge and bar 
when cold and picked over. The large pieces of iron are 
picked out and thrown in a pile for remelting. The coke is 
thrown in a pile to be taken to the scafTold or core oven furnace. 
Anthracite coal that has passed through a cupola and been sub- 
jected to a high heat will not burn alone in a stove or core oven 
furnace, and it is very doubtful if it produces any heat when 
mixed with other coal and again put in the cupola, and only the 
large pieces are picked out, if any. 

The cinder, slag and other refuse are shoveled into a wheel- 
barrow and taken to the rattle-barrels or dump. If the sand 
bottom is to be used over again it is riddled out in a pile and 
wetted. If not, it is removed with the cinder and slag. As 
soon as the bulk of the dump is removed the melter goes into 
the cupola and breaks down the ring of cinder over the tuyeres 
and chips off any that may be adhering to other parts of the 
lining. The dump is then all removed and the floor around the 
cupola is cleaned up preparatory to daubing up. Nothing is 
done with the dump after it is taken from the cupola but to re- 
cover the iron from it. This is done in two ways, by picking it 
over or milling it. The iron is often of the same color as the 
dump, and so mixed with it that it is almost impossible to re- 
cover it all by picking unless a great deal of time and pains be 
taken ; and it is cheaper to throw out only the pieces of pig 
and shovel all the remainder into the tumbling barrels, where 
it is separated in a short time and all the iron recovered that is 
worth recovering. 

CHIPPING OUT. 

Before going into the cupola to chip it out the melter slushes 



I02 THE CUPOLA FURNACE. 

one or two buckets of water around the lining from the charging 
door to lay the dust. He then goes in from the bottom if he 
can get in, but if the cupola is so badly bridged that he cannot 
get up into it he takes a long bar and endeavors to break down 
the bridge from the charging door, or goes down into it from the 
charging door, and with a heavy bar or sledge breaks it down. 
As soon as he gets a hole through large enough to work in, he 
goes down through it and with a sledge or heavy pick breaks 
down the shelf of slag and cinder that always projects from the 
lining over the tuyeres. He then takes a sharp pick and trims 
off all projecting lumps of cinder and slag and gives the lining 
the proper shape for daubing up. It is not necessary or advis- 
able to chip off all the cinder and adherent matter down to the 
brick, for the cinder stands the heat equally as well as new 
daubing, and in some cases better. But all soft honeycombed 
cinder should be chipped off, and all projections of hard cinder 
that are likely to interfere with the melting or tend to cause 
bridging should be removed. 

Some melters have a theory that to prevent iron running into 
the tuyeres they must have a projection or hump on the lining 
over the tuyeres, and they let the cinder build out from 3 to 6 
inches thick and 6 to 12 inches deep at the base. These humps 
tend rather to throw iron into the tuyere than to keep it out, 
for the fuel becomes dead under the hump and the iron in its 
descent strikes the hump and follows it around into the tuyere. 
They also form a nucleus for bridging. The refuse of melting 
as it settles lodges upon these humps and is chilled by the blast. 
A small cupola with these humps over the tuyeres will not work 
free for more than an hour, while the same cupola with the 
humps removed and the lining straight would work free for two 
hours and dump clean. They also interfere with the melting 
and in large cupolas cause bridging. All humps that form on 
the lining above the melting point from bad charging or other 
causes should be removed, for they hang up the stock and re- 
tard melting. 

The cupola picks generally used are entirely too light for the 



CUPOLA MANAGEMENT. IO3 

work to be done with them, and the handles are not firm enough. 
When the melter strikes a blow he cannot give the pick force 
enough to cut away the point desired and the handle gives in the 
eye, so that the pick glances off and cannot be held to the work. 
Repeated blows with a light pick turn the edge and render the 
pick worthless and the melter has to do two or three times the 
work really necessary in chipping out the cupola, and then he 
does not get it right. What the melter wants is a heavy pick 
with a firm handle. Then he can hold the pick where he 
strikes and prevent it glancing off. He can strike a blow that 
will cut away the cinder at one stroke and not jar and injure 
the lining nearly so much as he would by repeated blows with 
a light dull pick. The melter should be provided with three 
picks made of the best steel, weighing 4, 6 and 8 pounds each. 
They should be furnished with iron handles solidly riveted in, 
or should be made with large eyes for strong wood handles. 
The picks should be dressed, tempered and ground as often as 
they get the least bit dull. 

DAUBING. 

After the cupola is chipped out the lining is repaired with a 
soft plastic adhesive material known as daubing, with which all 
the holes that have been burned in the lining are filled up and 
thin places covered, and the lining given the best possible shape 
for melting and dumping. There are a number of substances 
used for this purpose, some of which are very refractory, and 
others possess scarcely any refractory properties whatever and 
are not at all suitable for the purpose. Molding sand is fre- 
quently used for a daubing. It is easily and quickly wet up 
and mixed, is very plastic and readily put on, but possesses 
none of the properties whatever requisite to a good daubing. 
It crumbles and falls off as soon as dry in exposed places, and 
a lining cannot be shaped with it. Furthermore, when put on 
in places from which it is not dislodged in throwing in the stock, 
it melts and runs down and retards the melting by making a 
thick slag that is readily chilled over the tuyeres by the cold 
blast. 



I04 THE CUPOLA FURNACE, 

Some of the yellow and blue clays are very adhesive and re- 
fractory, and make good daubing alone or when mixed with a 
refractory sand. Ground soapstone and some of the soapstone 
clays from coal mines make excellent daubing. But probably 
the best and most extensively used is that composed of 
fire clay and one of the silica sands known under various 
names in dififerent sections of the country, and which we shall 
designate sharp sand. Fire clay is very plastic and adhesive 
when wet, but shrinks and cracks when dried rapidly. Sharp 
sand alone possesses no plastic or adhesive properties whatever 
and expands when heated. When these two substances, in ex- 
actly the right proportions, are thoroughly mixed, they make 
a daubing that is very plastic and adhesive, does not crack in 
drying, neither expands nor shrinks to any extent when heated, 
and resists the action of heat as well as fire-brick in a cupola. 
When not evenly mixed the fire clay cracks and the sand ex- 
pands and falls out of the clay when heated, making an uneven 
and uncertain daubing. 

Fire clay absorbs water very slowly, and it requires from I2 
to 24 hours' soaking before it becomes sufficiently soft to be 
thoroughly and evenly mixed with the sand. A large soaking 
tub should be provided near the cupola and it should be filled 
with clay every day after the cupola is made up, and the clay 
covered with water and left to soak until the next heat. The 
clay and sand cannot be evenly mixed in a round tub with a 
shovel, therefore a long box and a good strong hoe should be 
provided for the purpose. The amount of sand a clay requires 
to make a good daubing varies from one-fourth to three-fourths, 
according to the qualities of the clay and sand, but generally 
one-half of each gives good results. The sand is added to the 
clay dry, or nearly dry, and the daubing is made as thick and 
stiff as it can be applied to the lining and be made to stick. 
The more it is worked in mixing the better, and if let lie in the 
mixing box for a day or two after mixing it makes a better 
daubing than if applied as soon as prepared. 

Nothing is gained by using a poor, cheap daubing, for it 



CUPOLA MANAGEMENT. IO5 

does not protect the brick lining, but falls off or melts into a 
thick tough slag which runs down and chills over the tuyeres 
and retards the melting by bunging up the cupola, and more 
fuel and time are required to run ofif the heat. The daubing is 
taken from the mixing box on a shovel when wanted for daub- 
ing and placed on a board under the cupola if the box is near 
at hand. When it is some distance from the cupola the daub- 
ing is placed in buckets or small boxes made for the purpose 
and conveyed to the cupola. The parts of the lining to be re- 
paired are first brushed over with a wet brush to remove the dust 
and wet the lining so that the daubing will stick better. The 
daubing is then thrown on to the lining with the hands in small 
handfuls ; it can be made to penetrate the cracks and holes 
better in this way than in any other, and stick better than when 
plastered on with a trowel. After the required amount has 
been thrown on in this manner, it is smoothed over with a trowel 
or wet brush and made as smooth as possible. 

SHAPING THE LINING. 

Daubing is applied to a lining for two purposes — viz., to 
protect the lining and to shape the cupola, the latter being by 
far the more important of the two. A great many melters 
never pay any attention to it, their only aim being to keep up 
the lining, and they pride themselves on making a lining last 
for one, two or three years. Nothing is gained by doing this 
if the melting is retarded by doing so and enough fuel con- 
sumed and time and power wasted every month to pay for a 
new lining. Besides, a lining will last just as long when kept 
in good shape for melting as when kept in a poor one, and the 
aim of the melter should be to put the lining in the best possi- 
ble shape for melting and make it last as long as he can. 

New linings are made straight from the bottom plate to the 
charging door when the cupola is not boshed. When it is 
boshed the cupola is made of a smaller diameter at and below 
the tuyeres, and the lining is sloped back to a larger diameter 
from about 6 inches above the tuyeres, with a long slope 



I06 THE CUPOLA FURNACE. 

of 1 8 or 20 inches. In the straight cupola, slag and cinder 
adhere in every heat to the lining just over the tuyeres, and if 
not chipped off close to the brick after each heat, gradually build 
out and in time a hard ledge forms that is difificult to remove. 
It furthermore reduces the melting capacity of the cupola by 
increasing the tendency to bridge. Above this point at the melt- 
ing zone the lining burns away very rapidly and in every heat 
a hollow or belly is burned in it at this point that requires re- 
pairing. Above the melting zone the lining burns away very 
slowly and evenly and seldom requires any repairing until it 
becomes so thin that it has to be replaced with a new one. 

The cinder and slag that adhere to the lining just over the 
tuyeres must be chipped off close to the brick every heat, and 
the lining made straight from the bottom plate to 6 inches 
above the top of the tuyeres. No projection or hump of more 
than ^ or ^ inch should ever be permitted to form or be 
made over the tuyeres to prevent iron running into them, and 
it should be placed right at the edge of the tuyere when it is 
thought necessary to make it. The upper edge of the tuyere 
lining should be made to project out a little further than the 
lower edge, and the brick lining should be cut away a little 
under each tuyere so that molten iron falling from the top of 
the tuyere will fall clear of the bottom side of the tuyere and 
not run into it. 

It is not necessary or advisable to fill in the lining at the 
melting zone and make it perfectly straight, as it is when it is 
new, for a cupola melts better when bellied out at the melting 
zone. It must, however, be filled in to a sufBcient extent for 
each heat to keep up the lining and prevent it being burned 
away to the casing. No sudden offsets or projections should 
be permitted to form or remain at the upper edge of the melt- 
ing zone, for the stock lodges in settling upon projections and 
does not expand or spread out to fill a sudden offset, and so 
the heat passes up between the stock and lining and cuts away 
the lining very rapidly. No sudden offset or hollow should be 
permitted to form at the lower edge of the melting zone over 



CUPOLA MANAGEMENT. IO7 

the tuyeres, for the stock will lodge on it in settling and cause 
bridging of the cupola. The lining should be given a long 
taper from 6 inches above the tuyeres to the middle of the 
melting zone, and a reverse taper from there to the top of the 
melting zone. The belly in the lining should be made of an oval 
shape, so that the stock will expand and fill it as it settles from 
the top, and not lodge at the bottom as it sinks down in melting. 
As the lining burns away above the melting zone the straight 
cupola assumes the shape of the boshed cupola, and only the 
lower taper is given to the melting zone. 

Daubing should never be put on a lining more than i inch 
thick, except to fill up small holes, and even then small pieces 
of fire brick should be pressed into it to reduce the quantity of 
daubing and make it firmer. All clays dry slowly and give up 
their water of combination only when heated to a high tem- 
perature. When daubing is put on very thick it is only skin 
dried by the heat of the bed before the blast goes on. The 
intense heat created by the blast glazes the outside of the daub- 
ing before it is dried through to the lining, and as there is no 
way for the moisture to escape, it is forced back to the lining, 
where it is converted into steam and in escaping shatters the 
daubing or tears it loose from the lining at the top. 

In the accompanying illustration. Fig. 19, is shown a sectional 
view of a cupola that we saw at Richmond, Ind., in 1875. This 
cupola was a small one, about 35 inches diameter at the tuyeres, 
and the average heat was about 4 tons. The melter was a hard 
working German, who knew nothing about melting whatever, 
and his only aim was to keep up the lining in the cupola. With 
this object in view he would fill in the hollow formed in the 
lining every heat at the melting zone with a daubing of com- 
mon yellow elay and make the lining straight from the tuyeres 
up. The daubing required to do this was from 2 to 4 inches 
thick all around the cupola, and was put on very wet. The 
heat dried and glazed this daubing on the outside before it was 
dried through. There being no way for the water to escape, it 
was converted into steam, and in escaping from behind the 



io8 



THE CUPOLA FURNACE. 



daubing tore it loose from the lining at the top. The fuel and 
stock in settling got down behind the daubing and pressed it 
out into the cupola from the lining until it formed a complete 
bridge, with only a small opening in the center through which 
the blast passed up into the stock. Before the heat was half 

Fig. 19. 




SECTION THROUGH BRIDGED CUPOLA. 



over all the iron melted was running out at the tuyeres, and the 
bottom had to be dropped. When the cupola had cooled ofT, 
the daubing and stock were found in the shape shown in the 
illustration, and when the bridge was broken down it was found 
to be composed entirely of daubing that had broken loose from 
the lining in a sheet and doubled over. 



CUPOLA MANAGEMENT. IO9 

This melter always had slow melting and difificulty in dump- 
ing. Some nights after dumping he would work at the tuyeres 
with a bar until eight o'clock before he got a hole through, "so 
the cupola would cool ofT by morning. The lining was not pro- 
tected by the thick daubing, but was cut out more by the re- 
peated bridging than if it had been properly coated with a thin 
daubing. We daubed this cupola properly and ran ofif two heats 
in it and melted the iron in less than half the time usually 
taken, and had no difificulty in dumping clean. 

The lining of the boshed cupola does not burn out at the 
melting zone in the same shape nor to so great an extent as in 
the straight-lined cupola, and in shaping the lining it is made 
almost straight from the top of the slope to the bosh up to the 
charging door. The taper from the bosh to the lining should 
start at 6 inches above the top of the tuyeres, and should not 
be less than 18 or 20 inches long, and must be made smooth with 
a regular taper so that the stock will not lodge on it in settling. 
Should the cupola be a small one with a thick lining and only 
slightly boshed and burn out at the melting zone similar to the 
straight cupola, it must be made up in the same way as the 
straight cupola. The great trouble with boshed cupolas is that 
the melter does not give a proper slope to the taper from the 
bosh, but permits a hollow to form in the lining over the 
tuyeres, in which the stock lodges in settling and causes bridg- 
ing out over the tuyeres. 

These directions for shaping the lining only apply to the 
common straight and boshed cupolas. Many of the patent 
and odd-shaped cupolas require special directions for shaping 
and keeping up the lining as it burns out, and every manufac- 
turer of such cupolas should furnish a framed blue print or 
other drawing, to be hung up near the cupola, showing the 
shape of the lining when new and the shape it should be put 
in as it burns away and becomes thin. Full printed directions 
should be given for chipping out and shaping the lining. All 
the improvements in cupolas are based on the arrangement of 
the tuyeres and shape of the lining, and when the lining gets 



no THE CUPOLA FURNACE. 

out of shape the working of the tuyeres is disarranged, and the 
cupola is neither an improved one nor an old style, and is gen- 
erally worse than either. More of the improved cupolas have 
been condemned and thrown out for want of drawings showing 
the shape of the lining and directions for keeping it up, than for 
any other cause. 

RELINING AND REPAIRING. 

When a cupola is newly lined the lining is generally made of 
the same thickness from the bottom to the top except when the 
cupola is boshed. The casing is then either contracted to form 
the bosh or it is formed by putting in two or more courses of 
brick at this point. The lining varies in thickness from 4)^ to 
12 inches, according to the size of the cupola, the heavier lin- 
ings always being put in large cupolas. The greatest wear on 
the lining is at the melting zone, where it burns away very 
rapidly. From this point up it burns away more gradually and 
evenly, but the greatest wear is toward the bottom, where the 
heat is the greatest, and so a cupola gradually assumes a funnel 
shape with the largest end down and terminating at the melt- 
ing zone, and the lining is always thinnest at about this point 
when it has been in use for some time. 

At and below the tuyeres the destruction of the lining by 
heat is very slight, and the principal wear is from chipping and 
jarring in making up the cupola. At the charging door the 
principal wear is from the stock striking the lining in charging. 
In the stack the lining becomes coated with sulphides and 
oxides and is but little affected by the heat. A stack lined 
with good material properly put in generally lasts the lifetime 
of the cupola. The length of time a cupola lining will last de- 
pends upon the amount of iron melted and the way in which it 
is taken care of, and varies from six months to three or four 
years when the cupola is in constant use. 

A lining burns away very rapidly at the melting zone, and if 
not repaired every heat would burn out to the casing in a few 
heats. Above the melting zone it burns away more slowly and 
evenly, and gets thinnest just above the melting point. From 



V.UPOLA MANAGEMENT. 1 1 I 

this point it gradually grows thicker up toward the charging 
door, where the wear is comparatively slight. The thickness 
of lining required to protect the casing where the heat is most 
intense depends upon the quality of the fire-brick and how the 
lining is put in. A lining of good circular brick made to fit 
the casing, and laid up with a good, well-mixed grout, remains 
perfectly solid in the cupola as long as it lasts, and may be 
burned down to i ^ inches in thickness, and even less, for sev- 
eral feet above the melting point. When the brick do not fit 
the casing and large cracks or holes have to be filled in with 
grout, and daubing or the lining is poorly laid up, it becomes 
shaky as it burns out and in danger of falling out, and it cannot 
be burned down so thin as when solid. 

It is therefore cheaper in the long run to get brick to fit the 
casing and have the lining well put in. It will then only be 
necessary to reline when the lining gets very thin almost up to 
the charging door. The lining at the melting zone, where it 
burns away the fastest, is often taken out for 2 or 3 feet above 
the tuyeres and replaced with a new one when it is not neces- 
sary to reline all' the way up. In repairing a lining in this way 
the same sized brick are generally used as were used in lining. 
The lining has been burned or worn away above and below the 
point repaired, and the new lining reduces the diameter of the 
cupola to the smallest at the very part where it should be the 
largest. The result is that the new lining is cut away faster 
than any other part, and after a few heats it is as bad as it was 
before the new section was put in. 

A better way of repairing a lining at the melting zone is to 
put in a false lining over the old lining. This is done by putting 
on a layer of rather thin plastic daubing over the old lining and 
pressing a split fire-brick into the daubing with the flat side 
against the lining. The brick are pressed into the daubing 
close together almost as soon as it is put on, and all the joints 
are filled up and the surface made smooth. A lining may be 
put in a cupola in this manner all the way around and to any 
height desired, or only thin places may be repaired, which is 



112 THE CUPOLA FURNACE. 

done without forming humps in the lining that interfere with 
the melting. 

A split brick is an ordinary fire-brick, only i inch thick in 
place of 2 inches, and is now made by all the leading fire-brick 
manufacturers. We believe we were the first to repair a lining 
in this way, some 20 years ago. The split brick could xiot then 
be procured from fire-brick manufacturers, and they were made 
by splitting the regular sized brick with a sharp chisel after 
carefully nicking them all around. When the regular split 
brick cannot be procured they may be made in this way. 
Most of the new brick split very readily and true, but bats from 
old lining generally spall oiT and are difificult to split. A lining 
of split brick can be put in almost as rapidly as the cupola can 
be shaped with daubing alone. The diameter of the cupola is 
not reduced to the same extent as with a section of new lining 
put in in the regular way, and the best melting shape for the 
cupola is maintained with only a reduction in the diameter of 
from 3 to 4 inches. This lining, when put in with a good 
daubing well mixed, lasts as long as an equal thickness of lin- 
ing put in in the regular way; and it can be 'put in at a great 
deal less expense for labor and material. It is, however, worth- 
less if put in with a poor, non-adhesive and unrefractory daub- 
ing. 



CHAPTER V. 

EXPERIMENTS IN MELTING. 

In visiting different foundries years ago, when the manage- 
ment of cupolas was not so well understood as at the present 
time, we found that there were many and different opinions held 
by foundrymen as to the point in a cupola at which the melting 
of iron actually took place. Some foundrymen claimed that 
melting was done from the tuyeres to the charging door, others 
that iron was only melted in front of the tuyeres by the blast 
and flame, on a similar principle to melting in an air furnace, and 
still others claimed that iron was only melted at a short distance 
above the tuyeres. These various opinions led to different 
ways of charging or loading cupolas. In some foundries one 
or two hundred-weight of iron were put in on the bed, then one 
or two shovels of fuel, then more iron and fuel in the same pro- 
portion, until the cupola was filled or loaded to the charging 
door. This way of charging mixed the fuel and iron together, 
and cupolas were charged in this way to melt from the tuyeres 
to the charging door. In other foundries from five to twenty- 
hundred weight of iron were placed on the bed and a layer or 
charge of fuel placed upon it to separate it from a second charge 
of iron of a similar weight ; which was again covered with a 
second charge of fuel to separate it from the third charge of iron, 
and the cupola in this way filled. This charging was done upon 
the theory that a cupola only melted at a short distance above 
the tuyeres. Foundrymen who were of the opinion that the 
iron was melted by the flame and blast charged their cupolas 
in a similar way, but made the charges of iron light and those 
of fuel heavier, using an extravagant amount of fuel for each 
heat. 

8 (113) 



I 14 THE CUPOLA FURNACE. 

To learn definitely at what point iron was really melted in a 
cupola, and also to ascertain something in reference to a num- 
ber of other points in melting, as to which we had found there 
was a wide difiference of opinion among foundrymen, we con- 
structed a small cupola with a light sheet-iron casing and a thin 
lining, through which tuyere and other holes could be easily cut 
and closed when not required. This cupola we connected with 
a Sturtivant Fan placed at a short distance from the cupola. 
The fan was entirely too large for the size of the cupola, but it 
was arranged to regulate the volume of blast supplied by in- 
creasing or decreasing the number of revolutions of the fan. 
On the blast pipe, near the cupola, we placed a very accurate 
steel spring air-gauge to ascertain the exact pressure of blast in 
each experimental heat. The cupola was eighteen inches 
diameter inside the lining, and we first put in two round tuyeres 
of four inches diameter and placed them on opposite sides of 
the cupola, twenty-four inches above the bottom. 

The first experiments made in melting in this cupola were for 
the purpose of learning at what point in a cupola iron melted, 
and at what point it melted first. To ascertain these facts we 
procured a number of small bars of No. i soft pig iron and 
placed ten of them across each other in the cupola, six inches 
apart from center to center, and fastened the ends of each pig 
in the lining so that they could not settle with the fuel as it 
burned away. At the ends of each pig we removed the brick 
lining and filled in the space between the ends of the pig and 
casing with fire-clay, and through this clay and the casing 
made a small hole through which the heat and blast would 
escape as soon as the iron melted and fell out of the lining. 
The first bar of iron was placed three inches above the bottom, 
and the others at intervals of six inches. When they had all 
been put in place the bottom door was put up, a sand bottom 
put in and the fire started in the usual way. As soon as the 
fire was burned up the cupola was filled with coke to the 
charging door, which was six feet from the bottom, and the 
blast put on. The fan was run very slowly during the heat and 



EXPERIMENTS IN MELTING. I I 5 

the air-gauge showed less than one ounce pressure of blast in 
the pipe at any time during the heat, and the greater part of 
the time showed no pressure at all. We attributed the light 
pressure of blast to the fact that no iron was placed in the 
cupola but the ten bars of pig iron, and the blast escaped freelv 
through the fuel. The pressure of blast would probably have 
been greater ff the fuel had been heavily weighted down with 
charges of iron closely packed in the cupola. The tap hole 
was made small and not closed during the heat, and the iron 
permitted to run out as fast as melted and a note made of the 
time at which it melted. Iron first appeared at the tap hole in 
three minutes after the blast was put on, and continued to flow 
freely until one pig was melted, as was shown by the weight of 
the iron when cold. The pig melted was the one placed six 
inches above the top of the tuyeres, as indicated by the escape 
of the blast from the holes placed in the casing at each end of 
the pig. After this pig had melted there was a cessation in the 
flow of iron from the tap hole for about three minutes, when it 
began to flow again and flowed freely until another pig was 
melted. The pig melted this time was the one placed twelve 
inches above the tuyeres, as indicated by the small holes at the 
ends of the pig. There was then a dribbling of iron from the tap 
hole for a short time, when it ceased altogether ; but the blast was 
kept on until the appearance of the flame at the charging door 
indicated that the fuel was all burned up, and the bottom was 
then dropped. 

When the cupola cooled off it was found that none of the 
four bars placed below the tuyeres had been melted or bent, 
and they showed no indications of having been subjected to 
an intense heat. The fifth bar, however, showed such indica- 
tions and was partly melted, but was still in place. This bar 
was placed across the cupola almost on a level with the tuyeres, 
and at a point where the blast met in the center of the cupola 
from the two tuyeres. The iron that dribbled from the tap 
hole, as mentioned above, was melted from this bar. The 
sixth and seventh bars had melted as indicated by the escape 



Il6 THE CUPOLA FURNACE. 

of blast from the small holes in the casing at the ends of each 
bar and were entirely gone. The eighth bar was badly bent 
and showed evidence of having been subjected to an intense 
heat, but was not melted at all. The ninth and tenth bars were 
in place and showed less signs of having been highly heated 
than the eighth bar. The iron from the two pigs melted was a 
shade harder than when in the pig, and the iron from the pig 
partly melted was two or three shades harder, showing that 
iron melted very slowly or burned off was hardened in the pro- 
cess, and we afterward found this to be correct in the regular 
way of charging a cupola. This heat showed that wi]th a light 
blast the cupola melted only from about the top of the tuyeres 
to twelve or fourteen inches above the tuyeres. 

For the next heat the two bars melted out were replaced by 
new ones, and the bent one was also removed and replaced by 
a straight one. The cupola was made up and fired in the same 
manner as in the former heat, and filled with fuel to the charg- 
ing door. The same sized tuyeres were used and the speed of 
the fan increased so as to give a four-ounce pressure of blast in 
the blast pipe, as indicated by the air-gauge. In this heat, as 
in the former one, the iron placed below the tuyeres did not 
melt, and the bars placed above the tuyeres at dififerent heights 
melted at different times. The sixth bar placed six inches 
above the top of the tuyeres was the first to melt. Then in a 
few minutes later the seventh bar melted, and still a few minutes 
later the eighth bar, placed eighteen inches above the tuyeres. 
These three bars melted rapidly after they began, and were 
melted within a few minutes of each other. The iron from the 
first bar melted was a little dull, but the iron from the other 
bars was very hot. There was no dribbling of iron from the 
tap hole after the pigs were melted, as in the former heat, and 
one pig placed higher in the cupola, was melted in this heat. 
There was no fuel placed in the cupola after the blast was put 
on and when the fuel required to fill it to the charging door, 
or about twelve inches above the top of the last pig, was all 
burned out, the bottom was dropped, and the cupola permitted to 



EXPERIMENTS IN MELTING. II 7 

cool off. When we went in to examine it, it was found that the 
fifth bar, placed opposite the tuyeres, which had to some extent 
melted in the former heat, showed no change and had not been 
subjected to so high a temperature in this heat. The sixth, 
seventh and eighth bars had been melted entirely out, as in- 
dicated by the escape of the blast through the small holes in 
the casing at the ends of each bar. The ninth bar was in place, 
slightly bent, and showed indications of having been subjected 
to a higher temperature than during the former heat. The 
tenth bar at that point showed no change from increase of heat. 
From this heat we learned that directly in front of the tuyeres 
and just above them, the heat was decreased by a stronger or 
greater volume of blast, and the melting temperature was raised 
to a higher level in the cupola ; for the heat had been decreased 
at the fifth bar to an extent that prevented it from melting at 
all, and increased at the eighth bar to so great an extent that it 
was readily melted. 

For the next heat we arranged the bars and cupola in exactly 
the same way, and increased the speed of the fan to give an 
eight ounce-pressure, as shown by the air-gauge. The melting 
in this heat was practically the same as in the last one just 
described. We had anticipated that the melting temperature 
would be raised to a higher level in the cupola by the increase 
of blast, and were very much disappointed when it was found 
that the results were the same as with a four-ounce pressure of 
blast. After thinking the matter over for several days, it oc- 
curred to us to put on the blast without charging the cupola 
and test the air-gauge with different speeds of the fan. In doing 
this it was found that with the fan running at the same speed 
that showed eight ounces pressure on the gauge when the cupola 
was in blast, the gauge showed six ounces pressure when the 
cupola was not in blast. We at once concluded that the tuy- 
eres were too small to permit so great a volume of blast to 
pass through them, and the pressure of blast shown by the 
gauge was due to the smallness of the tuyeres, and not to the 
resistance offered to the blast by the stock in the cupola. 



Il8 THE CUPOLA FURNACE. 

Since making this discovery, we have seen a great many 
cupolas when in blast show a high pressure of blast on the air- 
gauge when the pressure was almost wholly due to the size of 
the tuyeres and very little blast was going into the cupola. 

After making the discovery that the tuyeres were too small 
to admit to the cupola the volume of blast produced by the fan, 
we placed two tuyeres in the cupola, four by six inches, laid flat. 
The tuyeres were made of this shape to increase the tuyere-area 
and at the same time neither raise the top of the tuyere nor 
lower the bottom, so that comparison of results in melting 
could be made with the former heat without rearranging the 
bars placed in the cupola. 

For the next heat we replaced the bars, melted out and 
made up, and charged the cupola as before and ran the fan 
at the same speed that had shown eight ounces pressure on the 
gauge with the small tuyeres. The result was that the gauge 
only showed a pressure of four ounces of blast. The sixth bar 
placed six inches above the tuyeres, which had been the first to 
melt in former heats, was not melted at all in this heat, and the 
seventh, eighth and ninth bars were melted in the rotation 
named at about the same time apart as in former heats. The 
tenth bar was not melted, and none of the bars below the 
tuyeres were melted. The iron from the ninth bar, which was 
placed twenty-four inches above the tuyeres and was the last to 
melt, was accompanied by a good deal of slag as it flowed from 
the tap hole, and the iron when cold was white hard, although 
it was No. I soft pig iron when placed in the cupola. The slag 
and hardness of the iron we attributed to the strong or large 
volume of blast used in this heat, as there had been no harden- 
ing of the last pig melted in former heats with a lighter blast. 
But this pig had remained in the cupola unmelted during the 
three former heats and been subjected to the heat of the cupola, 
and it was afterwards found that the hardness and slag were 
due to the roasting and burning of the iron in these heats, and 
not to the strong blast as at first supposed. In this heat the 
melting temperature was raised to a higher level in the cupola, 
but only three bars were melted as before at a lower level. 



EXPERIMENTS IN MELTING. II 9 

For the next heat we placed two more tuyeres in the cupola 
at the same level and of the same size as those used in the last 
heat, and arranged the cupola as before with a view to melting 
the tenth or top bar. The spread of the fan was the same as in 
the last heat, in which the gauge showed four ounces pressure 
of blast with two tuyeres. In this heat with double the tuyere- 
area, the gauge indicated a pressure of about one ounce, show- 
ing that the tuyere was still too small in the last heat to permit 
the blast to escape freely from the blast- pipe into the cupola. 
We were standing near the spout during this heat with our 
watch and note-book in hand, waiting to time the first appear- 
ance of iron at the tap hole and thinking it was a long time in 
coming down, when our assistant reported there was no flame 
or heat at the charging door, and the fire must have gone out. 
We at once examined the charging door and found that noth- 
ing but cold air was coming up. We then stopped the fan and 
removed the tuyere pipes, and found there was no fire in the 
cupola at the tuyeres. The front was then removed and 
plenty of fire was found in the bottom of the cupola, which 
immediately brightened up. The fire had been well-burned up 
as we supposed, above the tuyeres, before the blast was put 
on, and it had not been on more than fifteen minutes. We 
were not satisfied with the results in this heat, and as the fire 
showed signs of burning up when the front was out and the 
tuyeres were opened, it was determined to let it burn up and 
try it again with the strong blast. After the fire had burned 
up until there was a good fiie at the tuyeres and we were quite 
sure the fuel was on fire to eighteen or twenty inches above 
the tuyeres, we put on the same volume of blast as before and 
watched the results at the charging door. At first the blast 
came up through the fuel quite hot, but the temperature grad- 
ually decreased until it became cold, and it was evident that the 
large volume of blast had put out the fire, and this was found 
to be the case when the tuyere pipes were removed. 

When the bottom was dropped there was fire in the bottom 
of the cupola, and the coke around the tuyeres showed that it 



I20 THE CUPOIA FURNACE. 

had been heated, but the coke in the upper part of the cupola 
showed no signs of having been to any extent heated. 

The fuel used in this heat was hard Connelsville coke in large 
pieces. Large cavities were formed under the bars of iron sup- 
ported by the lining in charging. The coke was not weighted 
down with iron in the cupola, and the blast escaped freely 
through the crevices between the large pieces. 

We afterward made a heat in this cupola with the same tuyeres 
and blast, and charged the cupola in the regular way. The 
iron melted in this heat was pig and small scrap, that packed 
close in the charges and did not permit the blast freely to 
escape through the fuel. The gauge in this heat showed a blast 
pressure of three ounces and the fire was not blown out, but 
the cupola did not melt so well as with a less volume of blast, 
and the iron was harder. 

These heats showed that iron is not melted in a cupola by 
the blast and flame of the fuel ; for if it were, the bars directly 
in front and over the tuyeres, where the blast was the strongest, 
would have been melted first and been the only ones melted. 
But the one in front of the tuyeres was not melted by a mild 
blast, and the one just over the tuyeres was not melted by a 
strong blast. 

The failure of the sixth and tenth bars to melt in the same 
heat, showed that iron is not melted in a cupola all the way 
from the tuyeres to the charging door, as it was years ago sup- 
posed to do by most foundrymen, when the fuel and iron were 
mixed in the cupola in place of being put in in separate charges, 
as is now commonly done. 

The raising of the melting temperature to a higher level in 
the cupola by increasing the blast, showed that there is a 
certain limited melting space or zone in a cupola in which iron 
melts, and that this melting zone may be raised or lowered by an 
increase or decrease of the volume of blast. However the depth 
of the melting zone is not increased by a strong blast, but the 
zone is placed higher in the cupola. It was also shown that 
iron cannot be melted in a cupola outside of this zone, either 



EXPERIMENTS IN MELTING. 121 

above or below it, for the bars placed above and below it were 
not melted with either a light or a strong blast. The putting out 
of the fire in the cupola by a very large volume of blast and the 
subsequent poor melting done with a large volume of blast 
when the cupola was charged in the regular way, showed that 
too much blast may be given to a cupola and the iron thereby 
injured. 

FUEL UNDER THE TUYERES. 

In the first two heats it was noticed that considerable coke 
fell from the cupola when the bottom was dropped, although 
the indications of the charging door were that all the fuel in 
the cupola had been burned up. We determined to learn 
where this coke came from, and in the third heat we kept the 
blast on until the cupola was well cooled off, and we then 
turned a stream of water into it from a hose until the fire was 
out and the cupola cold. The ashes and cinder were then re- 
moved from the tuyeres, and it was found that there was no 
fuel above them except a few small pieces that had been buried 
in the ashes and cinder. The bottom was let down gradually, 
and the cupola found to be filled with coke and very little ashes 
from the bottom to the tuyeres. 

The coke when examined showed that it had been heated 
through, and was soft and spongy like gas-house coke, and 
totally unfit for melting purposes. When put into the cupola 
it was hard Ccnnelsville coke. We thought that all the ash 
found in the coke was made by the burning up of the bed before 
the blast was put on, and that the coke was not consumed at all 
after the blast was put on ; but we had no means of accurately de- 
termining this point. We afterward put a number of peep holes 
in the cupola at different points below the tuyeres to observe 
the action of the fuel at this point. The holes were arranged 
with double slides, the inner one with mica and the outer one 
with glass. The mica was not affected by the heat, and could 
be withdrawn for a few minutes and the action of the fuel 
observed through the glass without the escape of the blast. 
Through these openings it was observed that the fuel was 



122 THE CUPOIA FURNACE. 

always at a white heat just before the blast was put on, but after 
the blast had been on for a short time it became a dull red 
and remained so throughout the heat. Molten iron could be 
seen falling through the fuel in drops and small streams. But 
the fuel was never seen to undergo any change or to settle 
down as it would do if it were burning away. From these ob- 
servations it was concluded that the fuel placed under the tuy- 
eres was not consumed during the time the blast was on, and 
that the only fuel burned in this part of the cupola was that 
consumed in lighting up before the front was closed. 

LOW TUYERES, 

After the failure to melt with the four large tuyeres, we placed 
two tuyeres, four by six inches, in the cupola, on opposite sides, 
three inches from the bottom or one inch above the sand 
bottom. The bars were placed in the cupola as before and 
the cupola filled with coke to the charging door, and a four- 
ounce pressure of blast put on, the same as in the heat with 
these two tuyeres when placed at a higher level, namely, 
twenty- four inches above the bottom. In this heat three bars 
were melted, but the quantity of slag that flowed from the tap 
hole with the iron was so great that we did not know where it 
came from and we were so afraid of the tuyeres being filled 
with slag or iron, that we failed to note the time the iron melted 
or the points we were looking for ; but something else was 
learned. 

We at first thought the slag came from tuyeres being placed 
so near the sand bottom, and when the coke with which the 
cupola had been filled was burned out and the heat over, we 
took out the front and raked out the fuel and ash in place of 
dropping the bottom, to see how badly the sand bottom had 
been cut up by the blast. It was found that it had not been cut 
at all and was as perfect as when put in and nicel}' glazed. The 
lining had not been burned out to any greater extent than in 
former heats when there was no slag, and we were at a loss to 
imagine where the slag came from. But when the iron that had 



EXPERIMENTS IN MELTING. 1 23 

been melted in this heat was examined, it was found where the 
slag came from. All the pigs melted were placed in the cupola 
at the beginning of the experiments and had remained there 
unmelted under the tuyeres during a number of heats, and the 
iron had been burned by the fire in the bottom of the cupola 
when lighting up and during the heats. When placed in the 
cupola this iron was No. t soft pig, but when melted it was as 
hard and brittle as glass, and fully two-thirds of it had been 
burned up and when melted converted into slag. 

The results of this heat were so unsatisfactory that we replaced 
the bars melted out and repeated the experiment. The results 
in this heat were practically the same as in the heat with the 
tuyeres placed twenty-four inches above the bottom. Three 
bars placed six, twelve and eighteen inches above the tuyeres 
were melted in the same rotation and in about the same time. 
There was no trouble with slag, and the cupola melted equally 
as well as when the tuyeres were placed twenty-four inches 
above the bottom. 

MELTING ZONE. 

These heats established the fact that there exists a melting 
zone in a cupola when in blast, and that iron cannot be melted 
in a cupola outside of this zone. The location of a melting 
zone in a cupola is determined by the tuyeres and the distance 
or height of the zone above the tuyeres by the volume of blast, 
and the depth of the zone by the volume of blast and charging 
of the cupola. In these heats the melting zone was lowered 
in the cupola twenty-one inches by lowering the tuyeres to that 
extent without making any change in the character of the melt- 
ing, and the zone could have been raised the same distance 
without making any differance in the melting. The zone was 
raised from one level to another above the tuyeres by increasing 
the volume of blast. In the first heat, with a light blast, a bar 
of iron placed on a level with the tuyeres was partly melted, 
and one placed eighteen inches above the tuyeres was highly 
heated and almost ready to melt. Bars placed above and 



124 THE CUPOLA FURNACE. 

below these two bars were very little affected by the heat, and 
bars between them were melted, showing that these two bars 
were on the edges of the melting zone, and the zone had a 
depth of about eighteen inches. In the next heat, with a largej 
volume of blast, the bar placed on a level with the tuyeres was 
not melted at all, showing that it was outside of the melting 
zone and the zone had been raised by the stronger blast. In 
the next heat, with a still larger volume of blast, a bar placed 
six inches above the- tuyeres was not melted, showing that the 
zone had again been raised by the volume of blast. In each of 
these heats a bar placed higher in the cupola was melted, show- 
ing that the depth of the zone remained about eighteen inches 
and the entire zone was raised to a higher level in the cupola, 
we attributed the raising of the zone by increasing the volume 
of blast to the fact that the blast was cold when it entered the 
cupola, and it was necessary for the air to pass through a 
certain amount of heated fuel and become heated to a certain 
degree before its oxygen entered freely into combination with 
the carbon of the fuel to produce an intense heat; and the 
greater the volume of cold air, the greater the amount of heated 
fuel it must pass through before it became heated. With a 
hot blast this would not have been necessary, and the zone 
would probably have remained stationary and the depth of the 
zone been increased. In heats that were afterward made in this 
cupola with fuel and iron charged in the regular way, we found 
that the location and depth of the zone were somewhat changed 
by the weighting down of the fuel with heavy charges of iron. 
These tests were made by carefully measuring the fuel in the 
cupola from the charging door after the fire was burned up and 
the fuel settled, and we took care to have the fuel burned as 
nearly alike in each heat as possible, and to have the fire show 
through the top of the bed before iron was charged. 

In a former heat, with only bars in the cupola, a bar was 
melted placed twenty-four inches above the tuyeres. We placed 
a bed of that height in the cupola and put a charge of three 
hundred weight of iron on it, and turned on the same blast with 



EXPERIMENTS IN MELTING. 1 25 

which we melted the bar at that height. The blast was on for half 
an hour before any iron melted, and the melting was very slow 
until about half the charge was melted, when it began to melt 
faster. This indicated that the iron was placed above the melt- 
ing zone and supported there by the fuel, and the fuel had to 
be burned away before the iron was permitted to come within 
the zone by the settling of the stock. 

In the next heat we placed the top of the bed two inches 
lower, and in each subsequent heat two inches lower, until it 
was lowered to ten inches above the tuyeres, and made the 
charges of iron the same, or three hundred weight. 

With a twenty-two inch bed, iron came down in twenty 
minutes and was hot, but melted slowly throughout the heat. 

With a twenty-inch bed, iron came down in ten minutes, 
melted hot and faster than in previous heats. 

With an eighteen-inch bed, iron came down in five minutes, 
and melted fast and hot throughout the heat. 

With a sixteen-inch bed, iron came down in four minutes, 
melted hot and fast at first, but toward the latter end of the 
charge the iron was a little dull, and as each charge melted the 
first part of it was hot and the latter part dull. 

With a fourteen-inch bed, iron came down in four minutes. 
Melted fast, but was too dull for light work. 

With a twelve-inch bed, the iron was very dull, and with a 
ten-inch bed it was so dull that it could not be used for general 
foundry work. With a light blast and low melting zone, the 
iron in these two heats would probably have been hot. 

In these experiments we obtained the best general results 
with a bed of eighteen to twenty inches, and we adopted this 
bed for further experiments. 

Our next experiments were to learn the depth of the melting 
zone in practical melting, and the amount of iron that should 
be placed in eaeh charge to melt iron of an even temperature 
throughout a heat. In these experiments we made the charges 
of fuel placed between the charges of iron at a ratio of one 
pound of fuel to ten pounds of iron. 



126 THE CUPOLA FURNACE. 

For the first heat we put in a bed of eighteen inches, on this 
bed four cwt. of iron on this iron forty pounds of coke, on 
the coke four cwt. of iron, and so on until the heat was all 
charged. The blast was the same as before, four ounces pres- 
sure with two large tuyeres. In this heat the iron melted hot 
and fast, and of an even temperature throughout the heat. 

For the next heat we made the charges of iron five cwt., and 
charges of coke fifty pounds. The results in melting were 
practically the same in this heat as in the former one. 

For the next heat we made the charges of iron six cwt., and 
coke sixty pounds. In this heat there was a slight change in 
the temperature of iron as the last of each charge melted. 

For the next heat the charges were, of iron seven cwt., and 
coke seventy pounds. The iron in this heat was a little dull 
when the last of each charge melted, and hot when the first of 
the next charge melted, making the iron of a very uneven tem- 
perature throughout the heat. How often have we seen cupolas 
melt in this way. In fact it is a common thing in the majority 
of machine and jobbing foundries for a cupola to melt iron of 
an uneven temperature, and moulders may be seen almost 
every heat standing round the cupola watching their chance to 
catch a ladle of hot iron to pour a light pulley or other piece 
of light work. The uneven melting is never attributed to im- 
proper charging, but to the mysterious working of the cupola. 

For the next heat the charges were, of iron eight hundred 
weight, and coke eighty pounds. In this heat the iron was hot 
until the last of the first charge, when it became dull. The first 
of the second charge was hot, but it soon became dull, and 
before the charge was all melted it was very dull. At the be- 
ginning of the third charge the iron livened up a little, but soon 
became too dull to pour the work and had to be put into the 
pig bed. In this heat we used exactly the same percentage of 
fuel (one to ten) between the charges as in the former heats, 
which should have raised the top of the bed to its former height 
after melting a charge of iron ; but it did not do so, as shown 
by the melting, and the iron became duller as the melting of 



EXPERIMENTS IN MELTING. 12/ 

the heat progressed. Had another charge of iron been put in, 
it probably would not have melted at all. The failure of the 
cupola to melt well in the latter part of the heat was not due to 
the heat being too large for the cupola, for we afterwards melted 
heats double the size of this one in the same cupola, and had 
hot iron to the end of the heat. The top of the bed was 
reduced to a lower level in this heat in melting the heavier 
charges of iron, and the fuel in the bed must have burned away 
more rapidly when the bed was low, or the charges of fuel would 
have restored it to its former height, as with the light charges 
of iron. We tried to determine this point more accurately by 
placing a vertical slot in the cupola at the melting zone in order 
to observe the settling of the charges, but the heat was so in- 
tense at this point that the heat could not be confined within 
the cupola, and the slot had to be closed up. 

In these experiments the most even melting was done with 
four and five hundred weight charges. With these charges the 
fuel kept the top of the bed at a proper height in the melting 
zone, while with heavier charges it became lower after the melt- 
ing of each charge, until it became too low to make hot iron, 
and if the charges had been continued, too low to melt at all. 
We afterward tried a number of heats with a twenty-inch bed and 
six hundred-weight charges, and did good melting. With a 
twenty-four inch bed and six hundred-weight charge the melt- 
ing was even, but slow. 

By the experiments in this cupola it was found that it was 
necessary to pass the blast through a certain amount of heated 
fuel before a melting zone was formed in a cupola, and that the 
amount of heated fuel required for the blast to pass through 
depended upon the volume of the latter. This heated fuel must 
be above the tuyeres, for the blast passes upward from the tuy- 
eres, and the melting zone is located at a point dependent upon 
the amount of heated fuel the blast must pass through before it 
becomes heated and forms the zone. The blast does not pass 
downward from the tuyeres except when it may be permitted 
to escape from the tap or slag hole, and fuel placed below the 



128 THE CUPOLA FURNACE. 

tuyeres takes no part in the melting of iron in a cupola. When 
the tuyeres are placed high, the fuel grows deader as the 
heat progresses and becomes a dull cherry red. We believe 
the fire would go out in this part of a cupola in a long heat 
were it not for the molten iron dropping through the fuel, and 
the occasional escape of blast from the tap and slag holes. 

Iron melted high in a cupola is made dull bypassing through 
a large amount of fuel below the tuyeres. With the tuyeres in 
this cupola placed three feet above the bottom and iron prop- 
erly charged to make hot iron, it was found impossible to get 
hot iron at the tap hole for light work. This was undoubtedly 
due to the iron being chilled in its descent through the fuel under 
the tuyeres, for the same charging and blast produced hot iron 
with low tuyeres. The amount of fuel under the tuyeres makes 
no difiference in the location of the zone, and it is the same 
distance above the tuyeres with high tuyeres as with low ones, 
when the blast is the same. No iron is melted outside of the 
zone, and fuel placed above the zone takes no part in melting 
until it descends into the zone. If too large a quantity of fuel 
is placed in a bed, the iron charged upon the bed is placed above 
the zone and cannot be melted until fuel in the zone is burned 
away and the iron settles into the zone, and iron is a long time 
in melting after the blast is put on. If too great a quantity of 
fuel is placed in the charges, the top of the bed is raised above 
the zone after the melting of each charge of iron, and fuel must 
again be burned away before the iron can settle into the zone 
to be melted, and there is a stoppage in melting at the end of 
each charge of iron. If the charge of iron is made too heavy, 
the bed is lowered to so great an extent in melting the charge 
that the top of the bed is not raised to the top of the zone by 
the charge of fuel ; and as each succeeding charge is melted, the 
bed sinks lower until it gets near the bottom of the zone and 
iron melts dull, or sinks below the bottom of the zone, and melt- 
ing ceases. Scarcely any two cupolas have the same tuyere 
area or receive the same volume of blast, and for this reason 
scarcely any two cupolas can be charged exactly alike. To do 



EXPERIMENTS IN MELTING. 1 29 

good melting in a cupola it is necessary for the melter to vary 
the amount of fuel in the bed until he finds the top of the melt- 
ing zone, and to vary the charges of fuel until he finds the 
amount of fuel that will raise the bed to the top of the zone 
after melting a charge of iron. He must vary the weight of 
the charges of iron until he finds the amount of iron that can 
be melted in a charge without reducing the bed too low to be 
properly restored by a charge of fuel. 

After twenty years' active experience in melting in different 
cupolas, the above are the only practical instructions we can 
give for charging and managing a cupola ; and no table of 
charges for cupolas of different sizes, with different tuyere-area 
and volume of blast, would be of any practical value to a melter. 
Fuel placed in a cupola above the zone to replenish the bed is, 
heated by the escaping heat from the zone, and prepared for 
combustion in the latter, and iron placed above the zone to be 
melted is heated and prepared for melting in it, and the more 
fuel and iron brought into a cupola at one time the greater 
the amount of heat utilized. And the charging door in a 
cupola should be placed at a sufftcient height to admit of a 
large amount of stock, or the entire heat, being put into the 
cupola before the blast is put on. 

The melting zone is developed above the tuyeres by permit- 
ting the blast or carbonic oxide to escape upward after passing 
through the zone, and it may be developed below the tuyeres, 
by permitting it to escape downward. A cupola has been con- 
structed with the tuyeres placed near the top, and provision 
made for the escape of the blast through flues arranged near 
the bottom of the cupola. It was hoped by this plan that all 
the heat produced by the fuel would be utilized in melting, 
and the entire heat placed in a cupola melted very quickly and 
economically. But these hopes were not realized, for the depth 
of the melting zone was not increased by being below the tuy- 
eres, but remained the same as above the tuyeres. Iron could 
not be melted outside of the zone, and the cupola was a failure. 
9 



I30 THE CUPOLA FURNACE. 

MELTING WITH COAL. 

All the experiments just described were made with Connels- 
ville coke, but we also made a number of similar ones in this 
same cupola with anthracite coal. In these experiments it was 
found that the melting zone was not so high above the tuyeres 
with the same volume of blast as with coke, nor was the depth 
of the zone so great, but the coal did not burn away so rapidly 
in the zone as coke and heavier charges of iron could be 
melted. In these experiments the best results were obtained 
with a bed of about fourteen inches above the tuyeres and 
charges of coal of one to eight, and charges of iron from one- 
half to two-thirds heavier than with coke. An opinion prevails 
among foundrymen that the tuyeres in a cupola must be espe- 
cially adapted for coke, or coke cannot be used. In these 
experiments we used the same tuyeres as with coke, placed 
them at the same heights, and found no difificulty in melting 
with them; and iron may be melted in almost any cupola with 
either coal or coke, if charged to suit the fuel and tuyeres. 

SOFTENING HARD IRON. 

In experimenting with iron in a crucible, we found that the 
hardest iron could be softened by melting it, or subjecting it 
to a prolonged heat in a closed crucible with charcoal. We 
thought the same results might be obtained in a cupola by pass- 
ing molten iron through charcoal in its descent from the melting 
zone to the bottom of the cupola. It had been found that fuel 
below the'tuyeres was not consumed during a heat, and we de- 
cided to try permitting the iron after melting to drop through a 
bed of charcoal under the tuyeres. The tuyeres were placed 
twenty- four inches above the bottom and the cupola was filled 
with charcoal to the tuyeres, and above the tuyeres coke to do 
the melting was placed. We were afraid the charcoal would all 
be burned up before the coke above the tuyeres was ready for 
charging, and to prevent this we put in a wood fire to dry the 
bottom and warm the cupola. When this was burned out we 
filled the cupola with charcoal to the tuyeres, put in shavings 



EXPERIMENTS IN MELTING. 131 

and wood, and lit the fire at the tuyeres above the charcoal. 
The charcoal was only burned a little on top when the coke was 
ready for charging, and not on fire at all in the bottom of the 
cupola. When the cupola was ready for charging we put in 
one charge of five cwt. of hard pig and scrap, and put on the 
blast. The iron melted hot, but in its descent through the 
charcoal to the bottom of the cupola was cooled to such an 
extent that it would scarcely run from the tap hole, and the 
heat was a failure. This was not the only failure in our exper- 
imental melting, and we are afraid if we attempted to write up 
all our experimental heats more failures than successes would 
be recorded. Experiments in a cupola are not always a suc- 
cess, no matter how much care may be taken in making them. 
Experimenters generally report only their successful experi- 
ments, but if they would report their failures also, they would 
give much valuable information and save other experimenters 
much time and expense in going over the same ground. 

For the next heat we placed shavings over the bottom, filled 
the cupola with charcoal to the tuyeres, and put shavings and 
wood on top of the charcoal for lighting the coke. There was 
a great deal of trouble in getting the two fires to burn at the 
same time, and the results were not at all satisfactory. 

For the next heat we filled the cupola with charcoal to a short 
distance above the tuyeres to allow for burning away, and 
settling, and lit the fire from the front in the ordinary way, and 
as soon as it was burned up to the tuyeres put in the front to 
shut off the draught at the bottom. This worked very well, and 
we found we had a good bed of hot charcoal up to the tuyeres 
when the cupola was ready for charging. On the bed of coke 
was placed a charge of five cwt. of pig and scrap, all white hard, 
and the blast put on. The charcoal bed did not appear to 
burn away at all during the heat, and the iron melted well aud 
came down hot. When tapped almost as fast as melted, the 
iron was very little softened by the charcoal. But when allowed 
to remain in the cupola for some tim.e after melting, it was 
softened to the extent of becoming a mottled iron when run into 



132 THE CUPOLA FURNACE. 

pigs or heavy work. But when held in the cupola for a suffi- 
cient length of time to soften it to this extent, the iron became 
very dull and not fit to run light work. This experiment was 
repeated a number of times with different grades of hard iron, 
but we never found any marked change in the iron when tapped 
almost as fast as melted and hot. When held in the cupola a 
sufficient length of time to soften it to a limited extent, it was 
too dull to run light work, for the flowing properties of the iron 
were not to any extent increased by the charcoal. As there is 
no difficulty in making mixtures of iron soft enough for heavy 
work into which dull iron can be poured, we could see no ad- 
vantage in using charcoal in this way. 

TIME FOR CHARGING. 

There is a wide difference of opinion among foundrymen as 
to the proper time for charging iron on the bed and putting on 
the blast after charging. Some claim that if iron is charged 
several hours before the blast is put on, fuel in the bed is 
burned up and the heat is wasted, and others claim that heat 
is wasted by putting on the blast as soon as iron is charged. 
In some foundries the cupola is filled with fuel and iron to the 
charging door before lighting the fire. In others, iron is 
charged after the fire is burned up and permitted to remain in 
the cupola two or three hours before the blast is put on, and in 
some foundries the blast is put on as soon as charging of iron 
begins. 

We made a number of experiments in the heats just described 
to ascertain the proper time for charging and putting on the 
blast after charging. Iron charged before the fire was lit was 
very uncertain as to the time at which it melted after the blast 
was put on. In some heats it melted in five minutes and in 
others in thirty minutes. 

Iron charged before the fire was burned through the bed was 
a long time in melting after the blast was put on, and the time 
of melting was very uncertain ; in some heats it melted in ten 
minutes, and in others not for thirty minutes. Iron charged 



EXPERIMENTS IN MELTING. I 33 

after the bed was burned through and the heavy smoke burned 
off, melted sooner after the blast was on and was more regular 
in time of melting, and generally melted in ten minutes when 
the bed was of a proper height. 

Iron charged two or three hours before the blast was put on, 
melted in from three to five minutes after it was put on. 

Iron charged and the blast put on as soon as charging began, 
melted in from fifteen to twenty minutes. 

In these heats it was found that time and power to run the 
blower were saved by charging the iron two or three hours 
before putting on the blast, for iron melted in from three to five 
minutes after the blast was on, and melted equally as fast during 
the heat as when the blast was put on scon after the iron was 
charged. We do not think that any fuel was wasted b}' this 
manner of charging, for we shut off the draught from the bottom 
of the cupola by putting in the front and closing all the tuyeres 
but one as soon as the bed was ready for charging. The bed 
burned very little after the front was put in, and the heat that 
arose from it was utilized in heating the first charge of iron 
preparatory to melting, or iron would not have melted in less 
time than when the blast was put on as soon as the iron was 
charged. There is great risk in charging iron before the fire is 
lit or has burned up, for the fire may go out or not burn up 
evenly, and we prefer to have the bed burned through before 
charging the iron. 

DEVICES FOR RAISING THE BOTTOM DOORS. 

A number of devices have been used for raising the bottom 
doors of cupolas into place, and thus avoiding the trouble and 
labor of raising them by hand. One of the oldest of these de- 
vices is a long bar, one end of which is belted to the under side 
of the door, on the other end is cast a weight or ball almost 
sufificient to balance the door upon its hinges when raised. 
When the door is down the bar stands up alongside of the 
cupola, and when it is desired to raise the door the bar and 
weight are swung downward. As the weight descends the 



134 fHE CUPOLA FURNACE, 

door is balanced upon its hinges and swings up into place, 
where it is supported by a prop or other support. This device, 
when properly arranged and in good order, raises the door 
very easily and quickly into place, but it is continually getting 
out of order. The sudden dropping of the door in dumping 
and the consequent sudden upward jerk given to the heavy 
weight on the end of the bar, frequently breaks the bar near 
the end attached to the door or breaks the bolts by which the 
bar is attached to the door, and the door is sometimes broken 
by the bar. For these reasons this device is very little used. 

Another device, and probably the best one for raising heavy 
doors, is to cast large lugs with a large hole in them, on the 
bottom and the door, and put in an inch and a half shaft 
of a sufficient length to have one end extend out a few inches 
beyond the edge of the bottom plate. The door is keyed 
fast upon the shaft, and the shaft turns in the lugs upon the 
bottom when the door is raised or dropped. An arm or crank 
is placed upon the end of the shaft, pointing in the same 
direction from the shaft as the door. When the door is down 
the arm hangs down alongside of the iron post or column 
supporting the cupola and is out of the wa\' in removing the 
dump, and when the door is up the arm is up alongside of the 
bottom plate, out of the way of putting in the bottom props. 
The door is raised by a pair of endless chain pulley blocks at- 
tached to the under side of the scaffold floor at the top and the 
end of the arm at the bottom, and it is only necessary to draw 
up the arm with the chain to raise the door into place. This 
is one of the best devices we have seen for raising heavy doors. 

Another one, equally good for small doors and less expensive, 
is to make the end of the shaft square and raise the door by 
hand with a bar or wrench five or six feet long, placed upon 
the end of the shaft. The bar is placed upon the shaft in an 
upright position, and by drawing down the end of the bar the 
door is swung up into place by the rotation of the shaft on to 
which it is keyed. When the door is in place the bar is re- 
moved from the end of the shaft, and is not at all in the way of 
handling the iron or managing the cupola. 



CHAPTER VI. 

FLUXING OF IRON IN CUPOLAS. 

Flux is the term applied to a substance which imparts 
igneous fluidity to metals when in a molten state, and has the 
power to separate metals contained in metallic ores from the 
non-metallic substances with which they are found in com- 
bination ; also to separate from metals when in a fluid state any 
impurities they may contain. Fluxes are also used for the pur- 
pose of making a fluid slag in furnaces to absorb the non- 
metallic residue from metals or ores and ash of the fuel, and 
removing them from the furnace to prevent clogging and to 
keep the furnace in good working order for a greater length of 
time. The materials used as fluxes for the various metals are 
numerous and varied in nature and composition, but we shall 
only consider those employed in the production of iron and the 
melting of iron for foundry work. 

The substances employed for this purpose are numerous, but 
they consist chiefly of the carbonate of lime in its various 
forms, the principal one of which is limestone. 

In the production of pig iron from iron ore in the blast fur- 
nace, limestone is used for the two-fold purpose of separating 
the iron from the ore, and for liquefying and absorbing the 
non-metallic residuum of the ore and ash of the fuel, and carry- 
ing them out of the furnace. For this purpose large quantities 
of limestone are put into the furnace with the fuel and ore. The 
stone melts and produces a fluid slag, which absorbs the non- 
metallic residuum of the ore and ash of the fuel in its descent 
to the bottom of the furnace. Thence it is drawn out at the 
slag hole, and carries with it all those non-metallic substances 
which tend to clog and choke up the furnace. By this process 

(135) 



136 THE CUPOLA FURNACE. 

of fluxing the furnace is kept in good smelting order for months, 
and even years. Were it not for the free use of limestone, the 
furnace would clog up in a few days. 

The blast furnace is a cupola furnace, and is constructed upon 
the same general principle as the foundry cupola. Foundry- 
men long ago conceived the idea of using limestone as a cupola 
flux. In many foundries it is the practice to use a few shovelfuls 
or a few riddlefuls of finely broken limestone in the cupola on the 
last charge of iron, or distributed through the heat, a few hand- 
fuls to each charge of iron. The object in using limestone in 
this way is not to produce a slag to be drawn from the cupola, 
but to make a clean dump and a brittle slag or cinder in the 
cupola, that can be easily broken down and chipped from the 
lining when making up the cupola for a heat. 

Limestone used in this way does not produce a sufficient 
quantity of slag to absorb the dirt from the iron and ash of the 
fuel and keep the cupola open and working free, but rather 
tends to cause bridging and reduce the melting capacity of the 
cupola. 

The making of a brittle cinder in a cupola by the use of lime- 
stone depends to a great extent upon the quality of the stone. 
Some limestones have a great afifinity for iron and combine with 
it freely when in a molten state, while others have but little 
afifinity for iron and do not enter into combination with it at all. 
In the cinder piles about blast furnaces we find cinder almost 
as heavy and hard to break as iron, resisting the action of the 
atmosphere for years; while at others we find a brittle cinder 
that crumbles to pieces after a short exposure to the atmo- 
sphere, or even slacks down like quicklimewhen wet with water. 
In a cupola we may have a hard or brittle cinder produced by 
limestone. The results obtained from the use of limestone in 
small quantities in a cupola are so uncertain that we do not think 
they justify the foundryman in using it. 

LIMESTONE IN LARGE QUANTITIES. 

The tendency of slag or cinder in a cupola is to chill and 



FLUXING OF IRON IN CUPOLAS. 1 37 

adhere to the lining just over the tuyeres and around the cupola 
at this point, and prevent the proper working of the furnace. 
So great is this tendency to bridge that a small cupola will not 
melt properly for more than two hours, and a large one for more 
than three hours. To overcome this tendency to clog and 
bridge, foundrymen in many cases have adopted the blast- 
furnace plan of using a large per cent, of limestone as a {\ux in 
their cupolas, and tapping slag. 

When a large per cent, of limestone is charged with the iron 
in a cupola, it melts when it settles to the melting point and 
forms a fluid slag. This slag settles through the stock to the 
bottom, and in its descent melts and absorbs the ash of the fuel 
and dirt or sand from the iron and carries them to the bottom 
of the cupola, where the slag and dirt it contains may be drawn 
ofT and the cupola kept in good melting order and in blast for 
days at a time. The amount of limestone required per ton of 
iron to produce a fluid slag depends upon the quality of the 
stone and the condition of the iron to be melted. It is the 
custom in some foundries, where the sprews and gates amount 
to from thirty to forty per cent, of the heat, to melt them with- 
out milling to remove the sand, and to use enough limestone in 
the cupola to produce a sufficient quantity of slag to absorb 
and carry out of the cupola the sand adhering to them. In 
this case a larger per cent, of limestone is required than would 
be necessary if the sprews and gates were milled and only clean 
iron melted. Poor fuel also requires a greater amount of slag 
to absorb the ash than good fuel, and a lean limestone must be 
used in larger quantities than a stone rich in lime. The quan- 
tity required to produce a fluid slag, therefore, varies with the 
quality of the limestone and the conditions under which it is 
used, and amounts to from 25 to JOG pounds per ton of iron 
melted. 

The weight of the slag drawn from a cupola when the sprews 
and gates are not milled, and the cupola is kept in blast for a 
number of hours, is about one-third greater than the weight of 
the limestone used. When the sprews and gates are milled, 



138 THE CUPOLA FURNACE. 

the weight of the slag is about equal to the weight of the lime- 
stone. When the cupola is only run for a short time and slag 
only drawn during the latter part of the heat, the weight of the 
slag is less than the weight of the limestone. 

The slag drawn from a cupola has been found, by chemical 
analysis, to contain from 4 to 7 per cent, of combined iron and 
numerous small particles of shot iron mechanically locked up 
in the slag. These cannot be recovered except at a greater 
cost than the value of the metal. In a number of tests made 
in the same cupola, we found the loss of iron to be from 3 to 4 
per cent, greater when the cupola was slagged. 

EFFECT OF FLUX UPON IRON. 

Many of the limestones and other mineral substances em- 
ployed as cupola fluxes contain more or less finely divided 
oxides, silicates, etc., in combination with earthy materials. 
The flux is often reduced in a cupola and its component parts 
separated, and in minute quantities they alloy with the iron and 
injure its quality. The conjoined effect upon iron of these 
diffused oxides, silicates, etc., liberated in a cupola from their 
native elements in fluxes, is to prevent the metal running clean 
in the mould or making sharp, sound castings, and the tensile 
and tranverse strengths are frequently impaired by them. When 
the oxides, silicates, etc., are not separated in the cupola from 
their native elements, they do not impair the quality of the 
metal, nor do they improve it. The tendency of the cupola 
furnace is to clog and bridge over the tuyeres, and concentrate 
the blast upon the iron through a small opening in the center 
and injure its quality. If by the free use of limestone we pre- 
vent bridging and keep the furnace working open and free, we 
avoid injuring the iron in melting by the concentration of a 
strong blast upon it. The effect, therefore, of limestone in a 
cupola is not to improve the quality of iron, but to prevent its 
deterioration in melting. 



FLUXING OF IRON IN CUPOLAS. 1 39 

THE ACTION OF FLUXES ON LINING. 

Limestone and other minerals employed as fluxes frequently 
contain impurities which enter into combination with the lining 
material of a furnace atid render it fusible. This was illustrated 
at the foundry of John D. Johnson & Co., Hainesport, N. J., in 
1893. The cupola front had been put in with new moulding 
sand for a long time, and no flux used in the cupola. The sand 
made an excellent front that resisted the action of the heat and 
molten iron upon it. As the heats enlarged, it became neces- 
sary to use flux and tap slag to run ofT the heat. Oyster shells 
were used and produced a slag that flowed freely and had no 
effect upon the sand in the front. When the supply of shells 
became exhausted, a limestone was used in place of them. 
Trouble then began with the front. It was melted by the flux 
into a thick, tough slag that settled down and closed up the tap 
hole, and iron could only be drawn by cutting away a large 
portion of the front to enlarge the tap hole. Mr. Johnson 
called at our ofifice to learn what could be done to keep the tap 
hole open. We advised that the front material be changed and 
a mixture of fire-clay and sharp sand be used in place of mould- 
ing sand. This was done, and there was no further trouble in 
keeping the tap hole open and in good order to run off the 
heat. This serves to illustrate the effect of fluxes upon lining 
material. With no flux and with oyster shells the moulding 
sand resisted the heat and pressure of molten iron and slag 
upon the front ; but with limestone it melted into a thick, 
tough slag. This was due to some property in the limestone 
efitering into combination with the sand and making it fusible. 
Had the cupola been lined with this moulding sand, the entire 
lining would have been cut out in one heat, while it would have 
stood many heats with shells or no flux at all. 

From the various qualities of cupola brick and lining mate- 
rial now in the market, a lining may be selected that will resist 
the action of almost any flux or slag, and foundrymen may 
select a flux to suit the linmg or a lining to suit the flux, which 
ever they find to be the most profitable in their locality. 



140 THE CUPOLA FURNACE. 

HOW TO SLAG A CUPOLA. 

Foundrymen sometimes experience trouble in slagging their 
cupolas. This is largely due to a lack of knowledge in charging 
the limestone and drawing the slag, for any cupola can be 
slagged if properly worked. To draw slag from a cupola, a suffi- 
cient quantity of limestone or other slag-producing material 
must be charged in the cupola with the iron to make a fluid 
slag. The exact amount required can only be learned by ex- 
perimenting with the fluxing material used, but it is generally 
from fifty to sixty pounds of good limestone per ton of iron, 
when the remelt is not milled. The limestone is generally 
charged on top of the iron and put in with each charge after 
the melter begins using it. No limestone is used with the iron 
on the bed or first few charges of iron. In small cupolas lime- 
stone is generally charged with the second or third charge of 
iron. In large cupolas, when the charges of iron are light, six 
or eight charges, or generally about one-sixth of the heat, are 
charged without limestone. This is the way limestone is used 
when the cupola is run in the ordinary way for a few hours. 
When the cupola is run for some special work, the limestone is 
charged in a number of dififerent ways. 

The slag is drawn from the cupola through an opening known 
as the slag-hole. This opening is made through the casing and 
lining under the lower level of the tuyeres and at a point in the 
cupola where it will be out of the way in removing iron from 
the spout and convenient for removing the slag. The height 
the slag hole is placed above the sand bottom depends upon 
how the iron is drawn from the cupola. When it is desired to 
hold iron in a cupola until a sufficient quantity is melted to fill 
a large ladle, the slag hole is placed high, and when the iron is 
drawn as fast as melted the slag hole is placed low. When the 
slag hole "is placed high, slag can only be drawn as the cupola 
fills up with iron and raises it to the slag hole. When the iron 
is withdrawn from the cupola, the slag falls and the slag hole is 
closed with a bod to prevent the escape of blast. When the 
iron is drawn from the cupola as fast as melted, the slag hole is 



FLUXING OF IRON IN CUPOLAS. I4I 

placed low and when opened it is permitted to remain open 
through the remainder of the heat. This is the best way of 
drawing slag from a cnpola, for the flow is regulated by the 
amount of slag in the cupola, and if the hole is not made too 
large, there is no escape of blast. 

The slag in the bottom of a cupola takes up impurities from 
the fuel and iron, and if permitted to remain in the cupola for 
too long a time, it may become so thick and mucky it will not 
flow from the slag hole. Or it may be filled with impurities, 
become over-heated, boil up and fill the tuyeres with slag; and 
when boiling, it will not flow from the cupola through a small 
slag hole. The time for drawing the slag from a cupola is 
therefore a matter of great importance. The slag hole is gen- 
erally opened in from half an hour to an hour after the cupola 
begins to melt, and when placed low is permitted to remain 
open throughout the remainder of the heat. When placed so 
high that slag can only be drawn when the cupola fills up with 
molten iron, it should be opened as soon as the slag begins to 
rise and closed as soon as it falls below the opening. 

DOES IT PAY TO SLAG A CUPOLA ? 

Nothing is gained by slagging a cupola when the sprews and 
gates are milled and the heat can be melted successfully in the 
cupola without slagging; but a great saving in labor and wear 
and tear of machinery can be effected in many foundries by 
melting the sprews and gates with the sand on, and slagging to 
carry the sand out and keep the cupola working free. A 
cupola can not be made to melt iron faster by slagging, but it 
can be kept in blast and in good melting condition for a greater 
length of time and a much larger amount of iron melted by 
slagging. Foundrymen who find their cupolas temporarily too 
small to melt the quantity of iron required for their work, can 
overcome the difificulty by slagging the cupola and keeping it 
in blast for a greater length of time. 

In endeavoring to make an estimate of the cost of slagging a 
cupola, we found that the cost of limestone in different localities 



142 THE CUPOLA FURNACE. 

varied from 50 cents to $3 per ton. The amount used varied 
from 25 to 100 pounds per ton of iron melted. The amount of 
slag drawn varied from 25 to 100 pounds per ton of iron. The 
iron combined with the slag varied from 4 to 7 per cent. With 
these wide differences in the cost and quantity of limestone 
used, and the difiference in the quantity of slag drawn and per 
cent, of iron it contained, we found it impossible to make an 
estimate that would be of any practical value to foundrymen. 
Such an estimate must be made at each foundry to be of any 
practical value. 

SHELLS. 

0)'ster, clam and other shells are largely composed of lime, 
and are frequently used as a flux in place of limestone in locali- 
ties where they can be procured at a less cost than limestone. 
The shells are charged in the same way as limestone and in 
about the same proportion to the iron. They may be used in 
place of limestone either in large or small quantities, and have 
about the same effect upon the iron and cupola as limestone. 
When used in large quantities, they produce a fluid slag that 
keeps the cupola working free and flows freely from the slag 
hole, carrying with it the refuse of melting that clogs the cupola. 
When the heat first strikes shells in a cupola, they produce a 
crackling noise and flakes of shell may be seen to pass up the 
slack, and the foundry roof, when flat, is often covered with 
flakes of shell after a heat, when shells are used in large quanti- 
ties. The crackling is due to the destruction of the hard inner 
surface of the shell; th5 flakes thrown from the cupola are en- 
tirely of this surface, and the loss of shell is not as great as it 
would appear to be at first sight. The remainder of the shell 
melts and forms a fluid slag that absorbs the refuse of melting, 
becomes thick and helps to clog up a cupola when the shells 
are used in small quantities, or assists in keeping it open when 
used in large quantities. 

MARBLE SPALLS. 

Marble is another of the carbonates of lime, and the spalls or 



FLUXING OF IRON IN CUPOLAS. 1 43 

chippings from marble quarries or works are quite extensively 
used in some localities as a cupola flux. Their action in a 
cupola and their effect upon iron is very similar to that of lime- 
stone, and they are used in the same way and in about the 
same proportions. There are a number of other substances, 
such as fluor-spar, feld-spar, quartz-rock and a number of 
chemical compounds that are used as cupola fluxes. 

In 1873, when engaged in tHe manufacture of malleable iron, 
we began experimenting with mineral and chemical materials 
with the view of making a cheap malleable iron, and changing 
the nature of iron in a cupola furnace so that it might be an- 
nealed at a less cost, and produce stronger iron. In this we 
succeeded to some extent, and then drifted off into improving 
the quality of iron in a cupola for grey iron castings; this we 
have followed for nearly twenty years. During this time we have 
melted iron in foundries all over the greater part of the United 
States and Canada, and have constructed and worked a number 
of experimental cupolas of our own, to learn the effect of dif- 
ferent mineral and chemical substances upon iron and cupola 
linings. In these investigations we have used all the mineral and 
chemical fluxes known to metallurgical science, and observed 
their effect upon the various grades of iron employed for 
foundry work. 

In these experiments it was found that iron can be improved 
or injured when melted in a cupola furnace, and is often ruined 
as a foundry iron by improper melting and fluxing. The point 
at which iron is melted in a cupola-has a great deal to do with 
its quality. Iron melted too high in a cupola is burned and 
hardened ; melted too low, it runs dirty in a mould ; melted 
with too strong a blast, it is hardened. Iron melted dull does 
not make a sound casting. Iron melted v^ith poor coal or coke 
is injured by the impurities in the fuel. Iron melted with oyster 
shells, limestone and other mineral fluxes may take up oxides, 
sulphides, phosphides, silicates and other impurities contained 
in the flux and be ruined by them for foundry work. 

The per cent, of iron lost in melting is increased by improper 



144 THE CUPOLA FURNACE. 

melting and fluxing, and maybe double or treble what it should 
be. We have made a great many experiments to ascertain the 
effect of silicon on iron, and have found that silicon enters freely 
into combination with cast iron and has a softening effect upon 
it. Iron as hard as tempered steel may be made as soft as lead 
by combining it with silicon. But silicon is an impurity hav- 
ing a deleterious effect upon iron. An excess of it destroys 
cohesive force ard crystallization, and reduces transverse and 
tensile strength. So great is the destruction of cohesive force 
in cast iron by silicon that the strongest iron may be reduced 
to a powder when combined with an excess of silicon. Silicon 
in any proportion is a detriment to cast iron, as an iron. The 
nature and form of crystallization of a pure cast iron is changed 
by sudden cooling in a mould, and a soft iron in the pig may 
become a hard iron in a casting, This chilling property in 
cast iron is destroyed by silicon, and an iron high in it is 
not hardened when run into a sand mould or upon an iron 
chill. The destruction of the chilling tendency in cast iron is 
very desirable in the manufacture of light castings, and for this 
reason silicon irons are largely used in foundries making this 
class of work. 

The per cent, of silicon an iron may contain and yet retain 
sufificient cohesive force for the work, depends upon the amount 
of other impurities in the iron and the work the iron is em- 
ployed to make. For heavy work, requiring great strength, it 
should contain none at all. For light machinery it may con- 
tain from one-half to one per cent. ; and for stove plate, light 
bench work, etc., it may contain from two to three per cent. 
This amount is sufificient to reduce the chilling tendency of the 
iron, without impairing its strength to any great extent in this 
class of work. But a larger amount destroys the strength of 
the iron and also injures its flowing property in a mould. 

At the present time there is a large amount of high silicon 
cheap Southern iron being used in stove foundries for the pur- 
pose of making a cheap mixture and a soft casting. At one of 
these foundries we recently visited, the foreman informed me that 



FLUXING OF IRON IN CUPOLAS. 1 45 

they were using a mixture that cost $14 per ton, and said their 
breakage in the tumbHng barrels and mounting shop was very 
large, and he never made a shipment to their warehouse in 
New York, a distance of 25 miles, but a lot of stoves were 
broken in transit and sent back to be remounted and repaired. 

At another stove foundry in Troy, N. Y., they informed us 
they were using a mixture of Pennsylvania irons that cost them 
$20 per ton. They had scarcely any breakage at their works, 
and shipped their lightest stoves and plate to their warehouse 
in Chicago without boxing or crating, and never had any break- 
age in transit or in handling. They had found by experience 
that a mixture of Pennsylvania irons at a cost of $20 per ton 
was cheaper in the long run than a mixture of cheap Southern 
irons at $14 per ton. 

In a number of other foundries we visited, they all complained 
of heavy breakage when using high silicon irons as softeners. 
Another matter to be considered in using these high silicon 
irons for stove plate, is, how long will a stove last, made of such 
weak iron, and can a reputation for good work be maintained 
by foundries using them? A stove made of this kind of iron 
will certainly not last as long as one made of good iron. 

Carbon has the same effect upon cast iron as silicon, in soft- 
ening and reducing the chilling tendency. The hardest of cast 
iron can be made the softest by the addition of carbon, without 
destroying its cohesive force and rendering it brittle or rotten, 
and carbon can be added to iron in a cupola as readily as sili- 
con. Before the high silicon Southern irons were put upon the 
Northern market, highly carbonized irons were used as softeners 
for stove plate and other light work, and a far better grade of 
castings were made then than now are made from the silicon 
irons. 

It is difificult to remove silicon from iron when melted in a 
cupola, but free carbon is readily removed by the oxidizing 
flame in a cupola produced by a strong and large volume of 
blast ; and a soft iron may be hardened in melting to such an 
extent as to make it unfit for the work. This can be prevented 
10 



146 THE CUPOLA FURNACE. 

to some extent by using a mild blast and melting the iron low 
in the cupola, and it can also be prevented by the use of chem- 
icals in the cupola to produce a carbonizing flame. 

We have spent a great deal of time and money in experiment- 
ing on the production of such a flame in a cupola as would not 
only prevent the deterioration of iron in melting, but would im- 
prove its quality, and at the present time are engaged in the 
manufacture of a chemical compound for this purpose. 

FLUOR SPAR. 

iFluor spar is extensively used as a cupola flux, in sections 
of the country where it is found native and can be procured at 
a moderate cost, and it has also been used to a considerable 
extent in other sections of the country, but the expense of 
transporting this heavy material has greatly retarded its use as 
a flux at any great distance from the mines. Fluor spar when 
used in sufficient quantities in a cupola, produces a very fluid 
slag that absorbs and liquefies the non-metallic residue of melt- 
ing with which it comes in contact; keeps the cupola open and 
working freely, and causes it to dump clean. But it also fluxes 
the cupola lining, causing it to burn out in a very short time, 
and for this reason it can only be used in large quantities with 
certain grades of lining material that are only afTected to a very 
limited extent by it. This quality of lining material can gen- 
erally be procured in the vicinity of the mine, but it cannot 
always be had at a moderate cost in other parts of the country, 
and for this reason it is frequently used with limestone to in- 
crease the fluxing properties of the limestone and reduce the 
injurious efifect of the spar upon the cupola lining. When used 
in this way, fluor spar greatly increases the efficiency of a 
poor limestone, and often enables a founder to use a cheap 
'limestone that could not be employed alone as a flux, while the 
limestone reduces the injurious efifect of the spar upon the lin- 
ing, and the two combined make an excellent flux for tapping 
slag in long heats. 

We have used fluor spar in a number of cupolas and with a 



FLUXING OF IRON IN CUPOLAS. 1 47 

great many different brands of iron. We never found it to harden 
or soften any of these irons to a noticeable extent, but it im- 
proved the meking very materially in a number of cases where 
the cupola was run beyond its melting capacity, melted slow 
in the latter part of the heat, and could not be dumped without 
a great deal of labor. 

CLEANIXG IRON BY BOILING. 

Before the use of fluxes in cupolas was so well understood 
as at the present time, it was a common practice in many 
foundries to cleanse iron of impurities in a ladle by agitating 
or boiling the molten metal. This caused a large amount of 
dross to collect on the surface, from which it was skimmed off 
and the iron was considered to be purer after the boiling. A 
favorite way of agitating iron in a ladle was to place a raw 
potato or apple on the end of a tap bar and hold it in the 
molten metal, near the bottom of the ladle, for a short time. 
The potato or apple contained a sufficient amount of moisture 
to agitate or boil the metal gently without exploding it, and 
the metal was said to be greatly benefited by this gentle boil- 
ing ; but practice has demonstrated that nothing is gained by 
boiling iron in a ladle, and the practice has long since been dis- 
continued in this country. 

A ball of damp clay placed upon the end of a tap bar was 
also used for boiling iron in a ladle, but this was not considered 
as good or as safe as an apple or potato, for if the clay chanced 
to be too damp, it caused the iron to boil violently and some- 
times to explode. 

Another favorite way of cleansing and mixing irons years 
ago was to pole the molten iron. This was done with a pole 
tu o or three inches in diameter, of green hickory or other hard 
wood. The pole was thrust into the molten metal in a ladle or 
reverberatory furnace, and the metal stirred with it. The effect 
of the green wood thrust into the metal was to cause it to boil 
around the pole, and as the pole was moved through the metal 
all parts of the metal were agitated, and a better mixture of the 



148 THE CUPOLA FURNACE. 

dififerent grades of iron melted was effected and a more homo- 
geneous casting produced. The poHng of iron was a common 
practice in many foundries twenty-five years ago, but we have 
not seen iron poled in a ladle for many years, and we believe 
the practice has been entirely discontinued with cupola-melted 
iron ; but poling is still practiced in many foundries in the mix- 
ing of iron in reverberatory furnaces for rolls and other cast- 
ings requiring a very strong homogeneous iron. 



CHAPTER VII. 

DIFFERENT STYLES OF CUPOLAS. 
OLD STYLE CUPOLAS. 

Before describing the construction of the cupolas now in 
use, a short account of the old-fashioned cupolas may be of in- 
terest to many founders who have not had an opportunity of 
seeing them or observing their defects, all of which defects 
should be avoided in modern ones. 

In Fig 20 is seen the old style cupola in general use through- 
out the country many years ago, many of which are still in use 
in some of the old-time small foundries. A square cast-iron 
bottom plate, with op'ening in the center and drop door, is 
placed upon a brick foundation at a sufificient height above the 
floor for the removal of the dump. An iron column is placed 
upon each corner of the plate, and upon these columns is placed 
another cast-iron plate, having an opening in the center for the 
top of the cupola. Upon this plate a brick stack is constructed 
to carry off the flame and unconsumed gases from the cupola- 
The stack plate was sometimes placed upon brick columns or 
brick walls, built on each side of the cupola, through which 
openings were made for manipulating the tuyere elbows. The 
stack was built square and of a much larger size than the in- 
side diameter of the cupola. It was not subjected to a very 
high heat, and was built of common red brick. These large 
stacks were not built very high and threw out very few sparks 
at the top, which was due to their size. The cupola was placed 
between the bottom and stack plate, and the casing was formed 
of cast-iron staves, which were held together by wrought-iron 
bands, drawn tight by draw-bolts placed through the flanged 

( 149) 



I50 



THE CUPOLA FURNACE. 



ends of the bands. When the casing was made tapering, the 
bands were placed in position when hot and shrunk on. The 
cupolas were only from six to eight feet high, and those of 



Fig. 20. 




OLD STYLE CUPOLA. 



DIFFERENT STYLES OF CUPOLAS. 151 

small diameter were generally made larger at the bottom than 
at the top, to facilitate dropping, and that a large quantity of 
molten iron might be held in the cupola for a heavy casting. 
The charging door was placed in the stack just above the stack 
plate. From two to four tuyeres were put upon each side 
of the cupola, one above the other, and from eight to ten inches 
apart. The tuyeres were supplied from a blast pipe ^n each 
side, to which was attached a flexible leather hose and tin or 
copper elbow for conducting the blast into the tuyeres. A 
small hole was made at the bend of the elbow for looking into 
the tuyere, and closed with a wooden plug. The tuyeres were 
frequently poked with an iron bar through these openings. 

When light work was to be cast, the upper tuyeres were 
closed with clay or loam, and the blast sent through the lower 
tuyere. When it was desired to accumulate a large amount of 
molten iron in the cupola for a heavy piece of work, the lower 
tuyeres were used until the molten iron rose to the lower edge. 
The tuyere elbows were then withdrawn and shifted to the next 
tuyere above, and the lower tuyere closed with clay or loam 
rammed in solid. The shifting of the tuyere elbows was con- 
tinued in this way until the necessary amount of molten iron for 
the work to be cast was accumulated in the cupola. When a 
heavy piece of work was to be cast, a sufficient quantity of fuel 
was placed in the cupola to bring the top of the bed some 
distance above the top of the highest tuyere to be used ; on the 
bed two cwt. of iron was charged, and a shoveful of coke and 
a cwt. of iron charged throughout the heat. The charging was 
raised a little in different sized cupolas, but the fuel and iron 
were always mixed in charging. The large body of molten 
metal frequently pressed out the front and sometimes the plug- 
ging of the tower tuyeres. After the iron was tapped, the stock 
in the cupola dropped so low that no further melting could be 
done with the blast in the upper tuyeres, and frequently the 
lower tuyeres were so clogged that they could not be opened, 
and the bottom had to be dropped. 

In practice it was found that in a cupola constructed large at 



152 THE CUPOLA FURNACE. 

the bottom and small at the top for the purpose of retaining a 
large amount of molten iron, the stock did not spread to fill the 
cupola as it settled, and a great deal of heat escaped through 
the space made between the lining and stock by the settling of 
the stock. It was also found that the shifting of tuyeres re- 
quired such a high bed that the cupola melted slowly, and a 
greater per cent, of fuel was consumed in large than in small 
heats. 

THE RESERVOIR CUPOLA. 

To overcome the objections to the tapering cupola and shift- 
ing of the tuyeres, and still be able to hold a large amount of 
molten iron in a cupola, the reservoir cupola. Fig. 21, was 
designed. 

The casing of this cupola was made of wrought iron, and the 
bottom section, to a height of from twelve to twenty- four inches, 
was constructed of one-third greater diameter than the upper 
section or cupola proper. This arrangement admitted of a 
large body of molten iron being held in the cupola without 
shifting the tuyeres. The metal was spread over a larger sur- 
face, which reduced the pressure on the breast, and did not 
leave the stock in so bad a condition for melting after a large 
tap was made as in the taper cupola, and melting could be con- 
tinued after a large body of iron was tapped. The reservoir 
cupola did faster and more economical melting in large heats 
than the tapered cupola, but in small heats the amount of fuel 
required for the bed was too large for economical melting. 

At the present time cupolas are made of the same diameter 
from the bottom to six or eight inches above the tuyeres. The 
tuyeres are placed at a height to suit the general run of work 
to be done, and when a heavy piece is to be cast, the iron is 
held in ladles and covered with charcoal or small coke to ex- 
clude the air. The molten iron can in this way be kept in 
almost as good condition for pouring as in the cupola, and 
the cupola is kept in better condition and melts faster and 
longer. 



DIFFERENT STYLES OF CUPOLAS. 
Fig. 21. 



153 




RESERVOIR CUPOLA. 



154 



THE CUPOLA FURNACE. 



In Fig 




STATIONARY BOTTOM CUPOLA. 

is shown the old style English cupola. This 
cupola is constructed upon a 
solid foundation of stone or 
brick work and has a stationary 
bottom of brick, upon which is 
made a sand bottom. The 
refuse, consisting of ash, cinder 
and slag, remaining in the cu- 
pola after the iron is melted, is 
drawn out at the front in place 
of dropping it under the cupola, 
as is now generally done with 
the drop-bottom cupola. These 
cupolas are generally of small 
diameter. The opening in front 
for raking out is about two feet 
square, and when the cupola is 
in blast, is covered with an apron 
of wrought iron. When the 
cupola has been made up for a 
heat, shavings, firewood and a 
small amount of coke are placed 
in it and ignited with the front 
open ; when the coke is well 
alight, a wall is built up with 
pieces of coke even with the 
inside of the cupola lining. 

Fig. 23. 




STATIONARY BOTTOM CUPOLA. 



DIFFERENT STYLES OF CUPOLAS. I 55 

The bed of coke is then put in, a round stick is placed in the 
spout to form the tap hole, and the front is then filled in with 
new molding sand or loam even with the casing, and rammed 
solid. The apron, Fig. 23, is then placed in position over the 
loam and wedged tight against it, to prevent it being forced 
out by the pressure of molten iron in the cupola. After the 
breast-plate is placed in position, the tap hole and spout are 
made up in the ordinary way. Some melters prefer to place 
the apron in position before lighting the fire, and put the breast 
in from the inside when making up the sand bottom. It is then 
rammed solid against the apron and made up to the full thick- 
ness of the brick lining of the cupola. When the heat has been 
melted the breast-plate is removed and the loam front dug out. 
After the loam front has been broken away, a sheet-iron fender 
is placed in front of the cupola to protect the workmen from 
the heat, and the raking out process begins. This is done by 
two men with a long two- pronged rake. If the refuse hangs in 
the cupola, it is broken down from the charging door with a 
long bar or by throwing in pieces of pig iron. These cupolas 
were extensively used in England, but never to any extent in 
this country. We saw one in Baltimore a few years ago, and 
believe this is the only one in use in this country ; but they 
are still in general use in England. 

EXPANDING CUPOLA. 

Fig. 24 is a sectional elevation of the expanding cupola, 
which is said to have melted very rapidly and with very 
little fuel. This peculiar form was designed to admit of the 
charging of a large quantity of iron before putting on the blast, 
for the purpose of utilizing all the heat produced by the com- 
bustion of the fuel. These cupolas were built of common brick, 
banded with wrought-iron bands and lined with firebrick. The 
diameter at the charging door was sixty inches and at the 
tuyeres thirty inches, or one-half the diameter at the charging 
door. Below the tuyeres the lining expanded to forty or even 
fifty inches, to give room for molten metal. The bottom was 



156 



THE CUPOLA FURNACE. 
Fig. 24. 




EXPANDING CUPOLA. 



DIFFERENT STYLES OF CUPOLAS. 1 57 

stationary, and the refuse after melting was drawn at the front. 
The cupola expanded from a level a little above the tuyeres to 
the bottom of the charging door, thence to the top of the stack 
it gradually contracted. 

The greatly increased diameter at the charging door certainly 
admitted of a large quantity of iron being placed in the cupola 
at one time, and the utilization of a very large per cent, of the 
heat in melting. The even taper of the lining insured the even 
settling of the stock, so that good melting should have been 
done in this cupola; but the best results obtained appear to 
have been about six and a half pounds of iron to the pound of 
coke. 

This old form might be used to advantage in the construc- 
tion of very large cupolas ; but in the ordinary sized cupola, 
practically the same results are obtained by boshing or con- 
tracting the lining at the tuyeres, and making it straight from 
the top of the boshes to the charging door. 

Ireland's cupola. 

Ireland's cupola, for which the inventor took out a number 
of patents in England about 1856, and which was largely used 
there about that time, was constructed of a variety of shapes 
and sizes, but probably the best design is that shown in sec- 
tional view Fig. 25. It is built with a bosh and contraction of 
the diameter at the tuyeres, and has a cavity of enlarged diame- 
ter below them to give increased capacity for retaining molten 
metal in the cupola. 

The cupola, of which a section is shown, was twenty-five feet 
high from bottom plate to top of stack, twelve feet from bottom 
plate to sill of charging door. The shell was parallel and fifty 
inches diameter to the charging door, thence it gradually 
tapered to two feet three inches at the top. There were two 
rows of tuyeres eighteen inches apart, eight in the upper row 
two inches diameter, and four in the lower row six inches 
diameter. The cupola was constructed with stationary bottom 
and draw front. 



158 



THE CUPOLA FURNACE. 

f'iG. 25. 




IRELAND'S DOUBLK TUYERE CUPOLA. 



DIFFERENT STYLES OF CUPOLAS. 1 59 

It was at first proposed to use a hot blast in the top row of 
tuyeres, but it was found to be difficult and expensive to heat 
the blast, and that nothing was gained by using the upper row 
with a cold blast, and they were closed and the cupola con- 
structed with only the lower row of tuyeres. The interior shape 
was slightly modified to give more space for retaining molten 
metal, while, at the same time, retaining the boshes and in- 
creasing the diameter of the bottom of the cupola, as seen in 
the Fig. 25. Two of these cupolas were used by the Bolton 
Steel and Iron Company in England, in melting the iron for a 
large anvil block weighing two hundred and five tons, for which 
two hundred and twenty tons of metal, including eight tons 
Bessemer steel, were used. 

The cupolas were each seven feet outside diameter, three feet 
nine inches diameter below the boshes in the crucible, and five 
feet diameter above and below the crucible. The blast was sup- 
plied from an external air-chamber, extending round the casing 
and delivered into the cupolas through tvvo rows of tuyeres 
placed eighteen inches apart, sixteen in the upper row of three 
inches diameter, and four in the lower row of eight inches diam- 
eter. The metal was melted in ten hours and forty-five minutes 
from the time of putting on the blast until the mold was filled, 
and only one hundred and twenty-five pounds of coke con- 
sumed per ton of metal. Slag was tapped from the slag hole 
A below the tuyeres throughout the heat. 

Ireland's center blast cupola. 

In Fig. 26 is seen a sectional elevation of Ireland's cupola 
with bottom tuyere. The height from bottom plate to top of 
stack is twenty-seven feet, from bottom plate to sill of charging 
door twelve feet. The casing is parallel from the bottom plate 
to charging door, and thence it gradually tapers to the top ; 
diameter of casing up to charging door four feet six inches, 
tapering to two feet six inches at the top of stack. The inside 
diameter at bottom of crucible, on the cupola hearth L is two 
feet six inches, contracting to two feet three inches at spring of 



i6o 



THE CUPOLA FURNACE. 
Fig. 26. 



M 







IRELAND'S CENTER BLAST CUPOLA. 



DIFFERENT STYLES OF CUPOLAS. l6l 

the bosh AA, and three feet nine inches diameter from top of 
bosh to charging door, whence it tapers to one foot nine inches 
at top of stack. Height of crucible four feet five inches, length 
of boshes from A A to BB, eighteen inches ; height from top of 
bosh to charging door, six feet seven inches. The blast is sup- 
plied from one tuyere placed in the center of the bottom of 
crucible. 

The tuyere hole through the iron bottom is nine inches 
diameter, into which is passed a seven and a half-inch water 
tuyere, the mouth of which, H, is two feet above the sand bottom 
L. A slag hole A^, five inches diameter, is placed just below 
the level of the mouth of the tuyere. P is the tap-hole and 
spout. 

This cupola melted three tons of iron per hour with two and 
a-half cwt. of coke per ton, but it does not appear to have given 
satisfaction, for it never came into general use in England or 
this country, and Mr. Ireland changed his plans and con- 
structs his cupolas with side tuyeres. 

voisin's cupola. 

In illustration Fig. 27 is seen a sectional elevation of Voisin's 
cupola, in which very good melting has been done. The shell 
is constructed of boiler plate with an external air chamber of 
the same material, extending all the way round the body of the 
cupola. This air chamber is supplied from two pipes, one on 
each side of the cupola. Two sets of tuyeres lead from the air 
belt into the cupola. The lovv'er set are oblong, four in number, 
placed at equal distances apart and at right angles to the air 
belt. The upper set are round, of less capacity than the lower 
set, are placed horizontally through the lining and diagonally 
to the lower set, so that they are between them at a higher level. 

Mr. Voisin claims through this arrangement of the tuyeres, 
that the escaping gases are burnt in the cupola, creating a 
second zone of fusion with those gases alone, and the second 
set of tuyeres obviates to some extent the evil effect of the 
formation of carbonic oxide in the cupola. 
1 1 



1 62 



THE CUPOLA FURNACE. 
Fig. 27. 




C — 1 



r — n 



voisin's cupola. 



DIFFERENT STYLES OF CUPOLAS. 1 63 

This cupola is constructed in slightly varying shapes inside 
the lining, but the following dimensions give a general outline 
of it: Vertical dimensions from bottom to offset below tuy- 
eres, one foot ten inches ; offset below tuyeres to lower end 
of bosh, two feet four inches ; length of bosh, one foot two 
inches; top of bosh to charging door, six feet ten inches; 
bottom of charging door to bottom of stack, two feet seven 
inches; taper to stack, three feet ten inches. Horizontal di- 
mensions: Below tuyeres, two feet; at tuyeres, one foot eight 
inches ; at top of bosh, two feet four inches ; at bottom of 
charging door, one foot ten inches ; at charging door, two feet 
seven inches. 

The casing is made straight from the bottom plate to taper to 
the stack, and to get the above dimensions it has to be lined 
with brick made specially for this cupola. 

Mr. Voisin has invented a number of dififerent cupolas, but 
this one is said in melting to give the best results. 

woodward's steam-jet cupola. 

In Fig. 28 is seen a sectional view, showing the construction 
of the Woodward steam-jet cupola, in use to some extent in 
England. This cupola is worked by means of an induced cur- 
rent or strong draught caused by a steam-jet blown up the 
cupola stack, which is very much contracted just above the 
charging door. There are several dififerent modes of applying 
the steam-jet, but the general principle will be at once under- 
stood from the figure (28). The cupola is constructed upon 
the general plan of the English cupola, with a stationary bot- 
tom and draw front. Two rows of tuyeres or air-inlets, as they 
are termed, are placed radially at two different levels. In the 
lower row there are four openings, varying in size from five 
to eight inches in diameter, according to the size of the cupola. 
In the upper row there are eight, varying in diameter from three 
to five inches. Each of the air-inlets is provided with a cover 
outside, which can be closed when it is desired to shut off the 
draught. The upper row of air-inlets is placed from ten to 



164 



THE CUPOLA FURNACE. 
Fig 28. 




WOOnWARD'S STEAM-JET CUPOLA. 



DIFFERENT STYLES OF CUPOLAS. 1 65 

fifteen inches above the lower row. The lining is contracted at 
the air-inlets to throw the air to the center of the stock, and en- 
larged below the air-inlets to admit of the retention of a large 
amount of molten iron in the cupola. 

The charges of fuel and iron are put in at the charging door 
A in alternate layers in the ordinary way, and the door tightly 
closed and luted to prevent the admission of any air. The 
steam is then turned on through the nozzle B connected with 
the boiler by steam-pipe D, and the air-inlets // opened for the 
admission of air. When the cupola is working, the draught 
has to be regulated by the melter and care taken to close any 
air-inlets near which iron is seen to accumulate in a semi-fluid 
state. The temperature at the spot where the iron chills will 
soon rise to a degree that will cause the iron to run freely, when 
the air-inlet may be again opened. All the iron to be melted 
is put in and the door closed before the steam is turned on- 
The charging may be continued throughout the heat, but the 
opening of the door has the same effect on the stock as shutting 
ofT the blast in the ordinary cupola, and the melting stops. The 
repeated opening of the door soon gets the cupola into bad 
working order and it bungs up in a short time. 

When it is desired to use the cupola for continuous melting 
or for a larger amount of iron than can be put in at one time, it 
is constructed with a side flue and feeding hopper, as shown in 
Fig. 29. The general construction and air inlets are the same as 
those shown in Fig. 28. The stack is removed and the feeding 
hopper A with a sliding door B at the bottom, to be worked by 
the lever D, is placed on top of the cupola. The flue H near 
the top of the cupola connects it with the stack M, and the 
draught is induced by a steam-jet from the nozzle N attached 
to the steam-pipe P. When filling the cupola, the bottom of 
the hopper is left open and the charges put in in the ordinary 
way until the cupola is filled. The bottom door of the hopper 
is then closed, and when the cupola is melting the charges of 
fuel and iron are put into the hopper and dropped into the 
cupola as the stock settles, and the door is at once closed to 
exclude the air at the top of the cupola. 



1 66 



THE CUPOLA FURNACE. 

Fig. 29. 




woodward's steam-jet cupola. 



DIFFERENT STYLES OF CUPOLAS. I 67 

It is asserted by those interested in this cupola that it effects 
a great saving in fuel over the ordinary blast cupola. The con- 
sumption of coke in melting a ton of iron is placed at one hun- 
dred and fifty pounds, a very low rate of fuel ; but the same 
results are also claimed to have been obtained in blast cupolas 
of good design when properly worked. 

The steam required to create the draught is only equal in 
quantity to what would be required by an engine for driving a 
fan or blower of sufficient power to work an ordinary cupola of 
the same size. Considerable saving is effected in the first cost 
of engine and fan or blower, besides the saving in wear and tear 
of machinery. 

The objection to this style of cupola is the slow melting, for 
it cannot be forced beyond a certain point, and when a large 
amount of iron is to be melted the cupola must be kept work- 
ing all day. This does not meet the views of the foundrymen 
of this country, who desire to melt their heats in from one to 
two hours from the time the blast is put on until the bottom is 
dropped, and with that object in view construct their cupolas. 

TANK OR RESERVOIR CUPOLA. 

In Fig. 30 is seen a sectional elevation of a reservoir cupola. 
This cupola was designed for the purpose of making soft iron 
for light castings. It only differs in construction from the 
ordinary type in the reservoir or tank placed in front, which 
may be attached to any cupola. 

The cupola is set high and the tank A is placed in front of 
it, with the cupola spout leading into it near the top. The 
molten iron is run from the cupola into the tank as fast as 
melted, and drawn from the tank-spout into the ladles as it may 
be required for pouring. The tank is made of boiler plate and 
lined with fire-clay or other refractory material, and is covered 
with an iron lid, lined likewise with same material. The spout 
and breast are made up the same as for an ordinary cupola. 
Before putting on the blast, the tank is filled with charcoal and 
closed with the cover; and as the iron melts, it is run into the 



1 68 



THE CUPOLA FURNACE. 



Fig. 30. 



Y^ 




TANK OR RESERVOIR CUPOLA. 



DIFFERENT STYLES OF CUPOLAS. 1 69 

tank, where it is allowed to remain a sufficient length of time to 
be carbonized and softened by the charcoal. 

These cupolas have been constructed in a number of dif- 
ferent ways ; the tank has been made of sufficient size to hold 
the entire heat of molten iron before pouring, so that the iron 
might be of an even grade throughout the heat and softened to 
a greater extent; and they have been riveted to the cupola 
casing and the lining continued from the cupola to the tank. 
In this latter case, the top is bolted or clamped to the tank and 
a tight joint made to prevent the escape of the blast, which has 
the same pressure in the tank as in the cupola. 

The tank cupola produces a softer iron than the ordinary 
cupola, but there is considerable additional expense attached to 
it in keeping up the tank and supplying it with charcoal. 
Another objection is the change made in the shrinkage of the 
iron ; that taken from the tank shrinks less than the same grade 
of iron when taken from the cupola, and when some parts of a 
machine or stove are made from the tank and other parts from 
the cupola, allowance must be made in the patterns for the 
difference in shrinkage. 

It is claimed by some founders that soft iron can be produced 
by putting a quantity of charcoal on the sand bottom, and 
placing the shavings and wood for lighting the bed on top of 
the charcoal. In lighting up, the charcoal is not burned, but 
remains in the cupola during the heat and may be found in the 
dump. This is the case if the tuyeres are high and the front is 
closed before lighting up, but if the tuyeres are low or the front 
and tap-hole are not closed, the charcoal will be burned out in 
lighting up the bed, the same as the wood. 

Tanks are, in England, used in connection with cupolas to 
some extent at the present time for mixing irons or to enable 
the founder to run a large casting or heat from a small cupola. 
The iron for an entire heat, requiring several hours to melt in a 
small cupola, is melted and run into the tank and drawn from 
the tank into the ladles at casting time. This makes a well- 
mixed and even grade of iron in all the castings and saves con- 



170 THE CUPOLA FURNACE. 

siderable time in casting, as the moulders are not obliged to 
wait for iron to melt, as is often the case, 

MACKENZIE CUPOLA. 

In Fig. 31 is shown a sectional elevation of the Mackenzie 
Cupola, designed by Mr. Mackenzie, a practical foundryman, 
and manufactured by Isbel-Porter Co., Newark, N. J. When 
this cupola was designed the only one in use was the common 
straight one with a limited number of very small tuyeres and low 
charging doors, and it melted very slowly. It was the custom in 
foundries at that time, to put on the blast at one or two o'clock 
and blow all the afternoon in melting a heat. Moulders gen- 
erally stopped moulding when the blast went on and a great 
deal of time was lost in waiting for iron. To save this time and 
get a few hours' more work from each moulder on casting days, 
Mr. Mackenzie conceived the idea of constructing a cupola that 
would melt a heat in two hours from the time the blast was put 
on until the bottom was dropped. He had discovered that the 
tuyeres in common use were too small to admit blast freely and 
evenly, and cupolas did not melt so well in the center as near 
the lining and tuyeres. To overcome this fault in the old 
cupola, and admit the blast to the stock evenly and freely, a 
belt tuyere was put in extending around the cupola, and to 
place the blast nearer to the center of the cupola at the tuyeres, 
the lining was contracted or boshed at this point. To avoid re- 
ducing the capacity for holding molten iron below the tuyeres, 
the lining just above the tuyeres was supported by an apron 
riveted to the cupola casing and the bosh made to overhang 
the bottom, leaving the cupola below the tuyeres of the same 
diameter as before boshing. 

This cupola, when first introduced, was known as the two- 
hour cupola and wrought a great revolution in melting and in 
foundry practice. Heats that had required half a day to melt 
were melted in two hours, the quantity of fuel consumed in melt- 
ing was reduced, the number of moulds put up by each moulder 
increased, and the cost of producing castings greatly reduced 



DIFFERENT STYLES OF CUPOLAS. 
Fig. 31. 



171 




MACKENZIE CUPOLA. 



172 



THE CUPOLA FURNACE. 



Many of these cupolas are still in constant operation, and for 
short heats of one or two hours, are probably the most eco- 
nomical melting ones now in use. In long' heats the tendency 
of the cupola to bridge at the bosh is so great, that it melts 
slowly toward the end of a heat and is frequently difficult to 
dump, especially if the cupola is a small one. 

We have had much experience in melting in these cupolas, 
and have found that slag and cinder adhere to the lining over 




the tuyeres and become very hard and difficult to remove, and 
if care be not taken to remove them after every heat it soon 
builds out, as shown in Fig. 32, which reduces the melting 
capacity very much, and increases the tendency of the cupola 
to bridge and hang up. The lining should be kept as near 



DIFFERENT STYLES OF CUPOLAS. 1 73 

the shape shown in -Fig. 31 as possible, and all building out 
over the tuyeres and bellying out in the melting zone, as far as 
possible, prevented. 

In the illustration (Fig. 31) is shown the cupola pit, com- 
monly placed under cupolas when they are set very low for 
hand-ladle work. The outlet to the pit may be placed at the 
front, back or side of the cupola as found most convenient for 
removing the dump. 

THE HERBERTZ CUPOLA.* 

The cupolas generally used either for melting iron or for any 
other purpose, are cupolas blown through one or several rows 
of tuyeres inserted at some distance above the hearth. The 
pressure of the blast varies in most cases from ^ pound to i 
pound, and the blast is obtained by blowing engines or blowers 
driven through belting and shafting by special steam engines. 
Such a plant, requiring as it does many mechanical appliances, 
consequently subject to continual care and repairs, is expensive. 
The Herbertz cupola, instead of being blown by blast forced 
from below through the melting material, is provided at its 
upper end with a steam-jet pipe, which in action creates a 
vacuum of from 3 inches to 4 inches of water in the upper re- 
gion of the cupola, while the air is allowed to enter freely at the 
lower part through an annular opening between the movable 
hearth and the upper shaft. 

The movable hearth, as shown in Fig. 33, is mounted on four 
screws, which by their common action lower or raise it at will, 
and thereby allow of a complete and easy regulation of the 
quantity of blast introduced through the annular opening. The 
screws work either in the standards of the cupola, as seen in 
Fig- 33, or are carried on a special car together with the hearth, 
so that this latter can be removed at any moment from under- 
neath the shaft. The steam jet is applied in the center line of 
the smoke pipe, which connects the cupola either directly with 
a special stack or is built like the down-comer of a blast furnace, 

* By J. B. Nau, New York. 



174 



THE CUPOLA FURNACE. 
Fig. 33. 




SwhM •>?<& o^<t& A^Q. 



^;:^^i^?^ 



SECTION OF HERBERTZ'S IRON-MELTING CUPOLA. 



DIFFERENT STYLES OF CUPOLAS. 1 75 

and connects the cupola with a horizontal underground flue lead- 
ing to any chimney. The top of the cupola is provided with a 
hopper hermetically closed while the melting is proceeding, and 
only open at regular intervals and for a very short time, when 
the charge is being introduced. 

The bottom of the hearth is provided with a door turning on 
hinges and kept tight by a lock. This door, once lowered after 
the melting is done, turns around the hinges and the contents 
of the cupola are dropped into an ash pit, where, after having 
been cooled with water, the unburnt coke can be collected and 
saved for the lighting of the cupola in the next melting. 

Three tuyeres are placed all around at the level of the bottom 
of the hearth. These tuyeres, as we shall see later on, are 
plugged up with sand during the melting, but are used before 
the melting in the kindling of the fire and to give access to the 
air necessary for combustion. 

The shaft is provided at two different levels with bull's-eyes, 
through which the fire can be watched. 

The application of a steam-jet to create draft in the cupola 
has many advantages. The only mechanical appliance re- 
quired is a small boiler supplying the necessary steam for the 
ejector. No blowing engine or steam engine with blower, shaft- 
ing, pulleys, belts, no blast pipe connecting the blower with the 
cupola, is necessary. The only repairs are those on the boiler 
and steam pipe, very light indeed, without mentioning the fact 
that oil for lubricating will be entirely dispensed with. But be- 
sides these already important advantages, some other features 
are met with. Most of the blowers, running at a speed of from 
1000 to 1200 revolutions or more per minute, produce some- 
times a noise, which often can be heard at a great distance. The 
Herbertz cupola runs without any appreciable noise, and can be 
established in any populous center without the slightest incon- 
venience to the neighborhood. Its top being closed, no sparks 
or flame are thrown out. The repairs to the movable hearth 
are very easy and can be done outside. 

In the United States it is as yet little known. For some 



iy6 



THE CUPOLA FURNACE. 



time, however, tests have been made with it at a car-wheel 
foundry in Eh'zabethport, N. J. 

This cupola is very well adapted for the melting of pig iron. 
The very reduced consumption of coke, claimed by the inventor 
to be as low as 4 to 5 per cent, of the weight of iron (or in 
other words, i pound of coke would be enough to melt 20 
pounds of iron), leads to the conclusion that the combustion 
of coke must be complete, or that the coke must be burnt com- 
pletely to carbonic acid, and thus generate the greatest possi- 

FiG. 34. 




HORIZONTAL SECTION. 



ble amount of heat. In order to prove this, test-heats have 
been made in Europe, and the analyses of the escaping gases 
showed that in most cases the whole amount of carbon was 
burnt to carbonic acid, while in a few other cases a very small 
proportion of carbon burnt to carbonic oxide. In one of these 
test-heats the mixture in the cupola was 1050 kg.* of Luxem- 
burg foundry iron No. 3 and 450 kg. of foundry scrap, a total 
of 1500 kg., or 1.5 tons. 

* I kilogramme = 2.2 lbs. 



DIFFERENT STYLES OF CUPOLAS. 1 77 

The melting coke was air dry and contained but 3 per cent, 
of water, 6.8 per cent, of ash and 1.037 P^^ cent, of sulphur; 
190 kg. of filling coke was put in the cupola and on top of it 
1000 kg. of pig iron. The total amount of coke used, including 
lighting coke, was 215 kg. to 1500 kg. pig iron. After the 
fusion was done, 6"] kg. of coke were taken out and could be used 
again for the next day's charge, so that the real amount of coke 
used was only 215 — ^T = 148 kg., or 9.9 per cent., whereas the 
real amount of melting coke was only 5 per cent. 

A careful weighing of the iron cast showed that 1460 kg., or 
97-33 pci" cent, of the original iron charged, was obtained, con- 
stituting a loss of only 2.66 per cent. The temperature of the 
molten metal was high, and amounted in part to 1300°. The 
escaping gases had the following composition : 

Carbonic Carbonic Oxygen. Nitrogen, 

acid. oxide. 

Before the steam-jet was acting 7.1 o 7.1 85.8 

Five minutes after steam-jet was acting 13. i o 6.5 80.3 
Twenty-five minutes after steam-jet 

was acting 9.25 o 7.0 83.75 

At the end of the cast (after 35 min- 
utes 13.3 o 6.3 804 

Average 10.71 o 6.73 82.60 

Another test heat with thoroughly wet gas coke was made. 
This coke contained nearly 20 per cent, of water and 7.5 per 
cent, of ash. About 1 2.7 per cent, of it was used (lighting and 
melting coke together). The loss in iron in this charge was 
only 3.45 per cent. The average composition of the gases was 
1 1 .5 of carbonic acid, 3.4 of carbonic oxide, 8.2 of oxygen, 76.9 
of nitrogen. It will be seen that in this last heat carbon did not 
burn entirely to carbonic acid, which was probably due to the 
increased amount of coke that had been charged intentionally. 

Nevertheless, the composition of these gases is still far more 
favorable than would be obtained with an ordinary blown cu- 
pola, where a certain number of analyses have shown that the 
escaping gases contain from 12.50 to 19.90 percent, of car- 
12 



178 THE CUPOLA FURNACE. 

bonic acid and 4.80 to 1 1.73 per cent, of carbonic oxide. The 
analyses show, furthermore, that in the case of the Herbertz cu- 
pola, the fuel is thoroughly utilized and yields the maximum of 
heat. 

To obtain such complete combustion it is necessary that the 
air should be in slight excess, and that this actually happens is 
shown by the presence in the gases of a certain amount of free 
oxygen. Several reasons have been advanced to explain this 
complete combustion of carbon to carbonic acid. The first is 
that the air enters the cupola all around the circumference in a 
thin sheet and gives rise to very uniform combustion. Another 
reason is the very reduced velocity with which the gases rise. 

In the ordinary blown cupola these gases are pushed upward 
with great pressure and velocity, and the combustion under 
such conditions cannot be obtained entirely in the lower regions, 
but some of the air will reach the upper regions unburnt, where 
it causes the reduction of part of the carbonic acid. 

The presence of free oxygen in the escaping gases of the 
Herbertz cupola, might lead to the supposition that it has 
a pernicious influence on the composition of the iron. Some 
of the elements in the pig iron, such as carbon, silicon and 
manganese, for instance, might be oxidized, and by their partial 
elimination deteriorate the quality of the iron. Not only is this 
not the case, but it seems that actual practice has shown that 
less carbon and silicon are eliminated from the iron in the 
Herbertz cupola, than in the ordinary blown cupola. This has 
been explained in the following manner: The combustion in 
this cupola takes place a little above the annular opening, and 
no flame is seen in the upper regions of the cupola, whereas in 
the ordinary cupola, combustion takes place through the entire 
length of the shaft and continues in a blue flame on top. In 
this case all the pig iron is more or less heated and pasty before 
it reaches the melting zone, and surrounded by an oxidizing 
atmosphere, the elimination of part of its elements is easy. 

In the Herbertz cupola, where the combustion takes place 
almost entirely in the lower regions, and where the upper re- 



DIFFERENT STYLES OF CUPOLAS. 1 79 

gions are less heated up, the pig iron better resists the influence 
of the ascending gases. 

It must be stated at once that the above tests extended only 
over one single charge of 1.5 tons, lasting in the first heat 35 
minutes. Had the work been continued for a certain length of 
time and had a greater number of charges been made, the con- 
sumption of fuel would have been considerably lowered, as for 
the following charge only melting coke would have been put in 
the cupola without any further addition of lighting coke. Then, 
if five consecutive charges had been made, we should have 190 
kg. of lighting coke and 5 X 75, or 375 kg. of melting coke (at 
5 per cent, of the weight of iron), or a total of 565 kg. And 
as ^J kg. of coke have been taken out of the cupola after the 
charge was over, this would leave 498, say 500 kg. of coke 
really burnt, which is equal to 6.6 per cent. In other words, i 
pound of coke would melt 15.15 pounds of iron. 

In the cupola working for a few weeks at Elizabethport, 
the consumption of coke for the melting proper amounted 
during the tests to 6 per cent. The cupola is rated as a 2 ton, 
melting 2 tons an hour. The outside diameter of the hearth is 
4 feet 7 inches, whereas the shaft has an outside diameter of 
only 4 feet 4 inches, and the total height from bottom plate of 
hearth to top of cupola is 13 feet 9 inches, when hearth and 
shaft are in contact with each other. The castings made during 
the tests were car wheels, and the mixture of iron put in the 
cupola was the same mixture of pig and scrap iron that had 
been used previously in the old ordinary cupola of the foundry, 
viz. : One-third No. i foundry iron and two-thirds car-wheel 
scrap. It was melted down with only 6 per cent, of coke, not 
counting the filling coke. Notwithstanding this very reduced 
amount of fuel, the iron began to melt rapidly. Ten to fifteen 
minutes after the steam was put on to create the draft, the first iron 
was tapped ofT. It was very good, and so hot that the men had 
to wait a few minutes before casting it into the molds. Though 
the iron mixture used in this test was the same as has always 
been made in the old cupola, it must be stated that the castings 



l8o THE CUPOLA FURNACE. 

obtained were too soft for car wheels and presented very little 
chill on the tire. In order to obtain a better chill it was deemed 
advisable to use nothing but car-wheel scrap on the second day. 
The result showed a marked improvement on the first day's 
work ; the chill was deeper and better. On the third day the 
mixture was one-fourth No. 3 foundry iron and three-fourths 
average foundry scrap. The use of this mixture constituted a 
large economy over what had been done in the ordinary cupola, 
and with it better results were obtained than with a mixture of 
one-third No, i foundry and two-thirds car-wheel scrap. The 
castings obtained were very tough and dense with y^g inch chill. 
The metal, too hot to be cast immediately after tapping, was 
very pure throughout the cast. 

The charge on this day was as follows ; 

Filling coke, 576 pounds. 

Melting coke, 6x 72 = 432 pounds. 

Liniestone, 6x 15 = 90 pounds. 

No. 3 foundry, 6x 300 = 1800 \ ^^^ ^^^^^^ 

Foundry scrap, 6x900= 5400 i 

The hearth in the cupola used at Elizabethport is mounted 
on a small car. This hearth, prepared and dried outside, was 
filled with wood shavings, wood and coke on top to the upper 
level. It was then pushed under the shaft, and raised by means 
of the screws until it came in contact with its lower rim. Fill- 
ing coke was then charged to the level of the highest bull's-eye, 
and fire started through the three tuyeres at the bottom of the 
hearth. After this the cupola was left to itself, working under 
natural draft through the three tuyeres at the bottom. When 
the filling coke was fully ignited the above-named charge was 
put on in alternate layers of iron, coke and limestone. When 
the filling was done, the hearth was lowered enough to form an 
annular opening of about i^ inches between the lower rim of 
the shaft and the top of the hearth. The tuyeres at the bottom 
were plugged with molding sand, and the cupola again allowed 
to work with natural draft through the annular opening, until 



DIFP^ERENT STYLES OF CUPOLAS. l8l 

the first iron was melting down. At this tnoment the steam-jet 
was put in action. The draft, which, when no steam was ap- 
pHed, had been equal to about y'g^ inch water column, rose at 
once to between 3 and 4 inches of water. From that moment 
on, the melting was regular, hot and rapid. The top of the cu- 
pola was kept tight and only opened at regular intervals to in- 
troduce the raw materials. Lighting coke was only used at 
the start ; all the subsequent charges were made with not more 
than 6 per cent, of coke, and continued regularly without any 
other addition. When the steam was applied, its pressure was 
80 pounds. The entire charge of 7200 pounds was melted in 
I hour and 24 minutes, which corresponds to 5140 pounds of 
pig iron melted per hour, say 2-| tons, instead of 2 tons. The 
vacuum created in the cupola remained between 3 and 4 inches 
of water as long as the level was kept constant. Toward the 
end of the charge, when this level became lower, the vacuum 
fell somewhat below 3 inches. No disagreeable noise was heard 
while the melting was going on, nor was any spark or flame 
seen at the top of the cupola. 

As soon as the melting was done and the last iron run out 
from the cupola, the bottom door of the hearth was opened and 
the ignited mass fell down into the ash pit, where, once the 
hearth pulled out, the entire content w^as cooled with water, and 
the remaining coke gathered to be saved as lighting coke in the 
following melting. After careful weighing of the iron cast from 
the cupola, it was found that the entire loss amounted to only 
3^ per cent., a very low figure when compared with the ordi- 
nary loss of at least 6 per cent, in an ordinary foundry cupola. 
It is remarkable also that a lower grade of iron can be taken 
and still the same results as in the ordinary cupola be obtained. 
Thus the tests at Elizabethport have conclusively shown that as 
good results were obtained with a mixture of one-quarter No. 3 
foundry iron and three-quarters foundry scraps when melted in 
the new cupola, as had been obtained with a mixture of one- 
third No. I foundry and two-thirds scrap iron when melted in 
the ordinary cupola. This may be explained by the reason 



1 82 THE CUPOLA FURNACE. 

that less carbon and silicon are eliminated from the iron when 
melted in the Herbertz cupola. 

HERBEKTZ CUPOLA USED FOR MELTING STEEL. 

The first tests made in the Herbertz cupola to melt steel were 
attended with success. Rail ends, old files and other iron or 
steel crop ends were melted together with a small amount of 
foundry iron, and with only 8 to lO per cent, of lighting coke. 
The molten metal was liquid enough to be cast easily. How- 
ever, when small steel castings had to be made it was soon dis- 
covered that the metal lacked fluidity, and in order to obtain 
better results, it was deemed advisable to work with heated air. 
Figs. 35 and 36 illustrate the construction of a cupola especially 
adapted to this kind of work. The cupola in all its parts is en- 
tirely similar to the steam-jet cupola used for the melting of pig 
iron, with the exception, however, that a certain number of 
wrought-iron pipes are laid in the brick work. The air enters 
at the top in a circular space, and from there is sucked down at 
once through the iron pipes to the lower part, where it enters 
the cupola. By its passage through the pipes it is heated to a 
temperature ranging from 500° to 1 100° F. and consequent!}- 
the temperature in the melting zone will be sufficiently increased 
to obtain a thoroughly liquid steel. Bessemer steel, as well 
as wrought-iron crops, were melted in this way, each separately 
and with the greatest success. 

For the casting of heavy steel castings especially, this cupola 
is better adapted than a crucible. On account of its direct con 
tact with the fuel at a high temperature, the percentage of 
carbon in the metal seems to slightly increase. No steel-melt- 
ing cupola is as yet working in the United States, but on the 
Continent of Europe their value seems to be more and more 
appreciated. 

For melting other metals or alloys, such as lead, copper, 
brass, etc., the cupola has recently been introduced in some 
European works. Especially bronze has been melted in an 
ordinary foundry cupola with the best results. The tempera- 



DIFFERENT STYLES OF CUPOLAS. 
Fig. 35. 



183 





'y///y///////////////////////M. 




HERBERTZ STEEL MELTING CUPOLA. 



1 84 



THE CUPOLA FURNACE. 



ture required in this case being lower than in the case of pig 
iron, the cupola worked with natural draft and without any use 
of the steam-jet. The fuel economy obtained seems to be very 
large. The total consumption amounted to only 12 per, cent., 
whereas in crucibles this consumption is sometimes as high as 
40 per cent. The fusion, even without the application of the 
steam-jet, is claimed to be nearly five times quicker than in the 

Fig. 36. 




crucible furnace, and the bronze obtained is even purer than the 
bronze remelted in crucibles. This is said to be due to the fact 
that during the fusion, the small amount of tin often found in 
bronze is burnt out and escapes in the shape of a white smoke. 
The loss of metal during the melting seems to be slightly in- 
creased on account of the elimination of the tin. The cupolas 
used in the remelting of these metals are the same as those 
used for the remelting of foundry iron. 



PEVIE CUPOLA. 

In Fig. 37 is seen the Pevie cupola, designed by Mr. Pevie, 
a practical foundryman of the State of Maine. The small 
cupolas, 18 to 24 inches, of this design are built square, with 
square corners in the lining, and larger ones are made oblong 
with square corners and 24 to 30 inches wide inside the lining, 
and any increase in the melting capacity of the cupola desired, 



DIFFERENT STYLES OF CUPOLAS. 
Fig. 37. 



185 




PEVIE CUPOLA. 



1 86 THE CUPOLA FURNACE. 

is obtained by increasing the length of the cupola in place of 
increasing the diameter; as is done with the round cupolas. 

Blast is supplied on two sides from an inner air chamber, 
through a vertical slot tuyere extending the full length of the 
sides of the cupola. 

The object of Mr. Pevie in constructing a cupola upon this 
plan was to supply an equal amount of blast to all parts of the 
stock and to produce even melting. This theory was correct, 
for blast was certainly more evenly distributed to the stock than 
with the small round tuyere then commonly used, and we saw 
excellent melting done in cupolas of this construction in the 
foundry of Mr. Pevie, in a small town in Maine (the name of 
which is forgotten), which we visited some twenty years since. 
But in cupola construction an even distribution of blast is not 
the only matter of importance to be considered ; for if it bridges 
and clogs up, the blast cannot do its work, no matter how evenly 
it may be distributed by tuyeres or by the construction of a cu- 
pola, and the peculiar construction of this cupola made the ten- 
dency to bridge very great. It was only by careful management 
that it could in long heats be prevented from bridging, when 
the lining was kept in its original shape, and for this reason it 
never came into general use. We know of only three of them 
at the present time in operation, one at Smithville, N. J., and 
two at Corry, Pa., and the shape of the linings in these cupolas 
has been greatly altered from their original form. 

Stewart's cupola. 

In Fig. 38 is seen a sectional view of a cupola in use at 
the Stewart Iron Works, Glasgow, Scotland. This cupola, 
which is one of large diameter, is boshed to throw the blast 
more to the center of the stock and reduce the amount of fuel 
required for a bed. Blast is supplied from a belt air-chamber 
extending around the cupola, through a row of tuyeres passing 
horizontally through the lining and a second row placed above 
and between the tuyers of the first row and pointing downwards, 
as shown in the illustration. The object of this second row of 



DIFFERENT STYLES OF CUPOLAS. 
Fig. 38. 



187 




STEWART'S CUPOLA. 



1 88 THE CUPOLA FURNACE. 

tuyeres is to increase the depth of the melting zone and increase 
the melting capacity of the cupola per hour. Attached to the 
top of the air-chamber at intervals of about two feet, is placed 
a vertical gas-pipe of two inches diameter, and from this pipe 
four branches of one-inch pipe lead into the cupola, about 
twelve inches apart. The object of these pipes is to supply a 
sufficient amount of oxygen to the cupola above the melting 
zone to consume the escaping unconsumed gas, namely car- 
bonic oxide (CO), above the melting zone, and utilize it in 
heating and preparing the iron for melting before entering the 
zone. The cupola melts very rapidly, and is said to be the 
best melting one in Glasgow. But it is very doubtful if the one- 
inch gas-pipe tuyeres contribute anything toward the rapid 
melting, for it is absurd to suppose that one-inch openings 
placed twelve inches apart vertically and two or more feet 
apart around the cupola, would supply a sufficient amount of 
oxygen to fill a large cupola to such an extent as to ignite 
escaping carbonic oxide in the center of the cupola. While 
they might supply oxygen for combustion of carbonic oxide near 
the lining, we do not think they would admit a sufficient amount 
to be of any practical value in melting, even if they admitted a 
volume of blast equal to their capacity when placed in the lin- 
ing. This they do not do, for they are frequently clogged by 
fuel or iron, filled with slag from melting of the lining, and as a 
lining burns away the ends of the pipes are heated and fre- 
quently collapse at the ends, and it is almost impossible to keep 
them open during a heat or to open many of them after a heat 
is melted. The rapid melting in this cupola is probably du-e to 
the arrangement of the first and second rows of tuyeres and the 
shape given to the inside of the cupola, which is excellent for 
cupolas of large diameter. 

THE GREINER PATENT ECONOMICAL CUPOLA. 

In Fig. 39 is shown the Greiner cupola, manufactured by The 
Greiner Economical Cupola Co., Kankakee, 111., for which the 
following claims are made : 



DIFFERENT STYLES OF CUPOLAS. 



189 



In placing the Greiner Patent Economical Cupola before the 
foundrymen and steel manufacturers in this country, we have 
the advantage of the splendid results already obtained with this 
cupola in Europe, where more than three hundred are in daily 
use. 

The adoption of the Greiner system of melting iron there has 



Fig. 39. 




THE GREINER PATENT ECONOMICAL CUPOLA. 



met with the most satisfactory results. In no case has the sav- 
ing of fuel been less than twenty per cent., and in some instances 
it has reached forty and even fifty per cent. 

The novelty of the invention consists in a judicious admission 



IQO 



THE CUPOLA FURNACE. 



of blast into the upper zones of a cupola, whereby the com- 
bustible gases are consumed within the cupola and the heat 
utilized to preheat the descending charges, thereby efTecting a 
saving in the fuel necessary to melt the iron when it reaches 
the melting zone. In order to fully explain the principle of its 
workings, we illustrate in Fig. 40 a cupola of the ordinary 



Fig. 40. 



Fig. 41. 




->D Df 



D 



-I 



1 

m 



SECTION OF ONE ROW TUYERE CUl'OLA. 



SECTION OF DOUBLE ROW TUYERE CUPOLA. 



design, with a single row of tuyeres or air inlets, A A. The in- 
coming air burns the^coke in front of the tuyeres to carbonic 
acid gas, a combination indicating perfect combustion. As 
this gas ascends through the incandescent coke above, most of 
it is converted into carbonic oxide by the absorption of an 
equivalent of carbon. The result of the combustion is, there- 
fore, a gas mostly composed of carbonic oxide (CO), indicating 
an imperfect utilization of the fuel, as one pound of carbon 
burned to carbonic acid (CO2) will develop 14,500 heat units; 
whereas, the same amount of carbon burned to carbonic oxide 
(CO) will only develop 4480 heat units, or less than one-third 
of the heat given by perfect combustion. 



DIFFERENT STYLES OF CUPOLAS. 



191 



To avoid this loss of heat, additional tuyeres have been placed 
at a short distance bb (Fig. 41) above the lower tuyeres to in- 
troduce air to consume the carbonic oxide (CO), but such 
arrangement does not have the desired effect, because the 
material at that place in the cupola has a very high tempera- 
ture, consequently the entering air also ignites the coke, so 
that the action at the lower tuyeres is simply repeated, and car- 
bonic oxide (CO) again formed at a short distance above bb. 
This led Mr. Greiner to the following conclusions : 
In every cupola there must be a point cc, (Fig. 42) above 
which the descending materials have not yet reached the tem- 

FiG. 42. 




SECTION OF GREINER LUPOLA 



perature necessary for the ignition of the solid fuel, while the 
ascending combustible gas is still warm enough to ignite when 
brought into contact with air. It is clear that air, if properly 
admitted above that point, will cause the combustion of the 
carbonic oxide (CO) without igniting the coke. 

But if all the air necessary for the combustion of the carbonic 



192 THE CUPOLA FURNACE. 

oxide (CO) be admitted at one place or in one horizontal row 
of tuyeres, the heat developed will very soon raise the tem- 
perature so as to set fire to the coke, producing loss of carbon 
as before. Hence the upper blast must not be introduced on a 
horizontal plane, but through a number of small tuyeres, 
arranged (either in the form of a spiral or otherwise) so as to 
embrace the higher zones of the cupola, and must be regulated, 
both as to pressure and arrangement and dimensions of pipes, 
according to the capacity of each particular cupola. 

The combustible gases are thus burned without heating the 
coke to incandescence, and the heat thus developed is utilized 
to preheat the iron and the coke, so that they reach the melting 
zone at a higher temperature and require less heat to effect the 
meltmg. 

Another point in favor of the Greiner economical cupola, 
and which is very important in most foundries and steel works, 
is that the application of the Greiner system will increase the 
melting capacity of the cupola, owing to the more rapid melt- 
ing in the fusion zone and to the additional room in the cupola 
that previously was occupied by the extra amount of coke not 
now required. Owing to the more rapid melting, a purer and 
better iron is obtained. 

As will be understood, the number, size, position and arrange- 
ment of the upper tuyeres vary considerably, according to the 
capacity of the cupola to which the system is to be applied. 

It can be readily adapted to existing cupolas, without mate- 
rial alteration being effected, while the only additional fittings 
necessary generally consist of a circular pipe connected by 
branches with the main blast box of the cupola, valves to regu- 
late the blast, and connecting pipes for the small tuyeres. 

COLLIAU PAIENT HOT BLAST CUPOLA. 

In Figs. 43 and 41 are seen external and sectional views of 
the Colliau patent hot blast cupola, designed by the late Victor 
Colliau, a civil engineer, who devoted a great deal of time to 
the study of cupola construction and management. The cu- 



DIFFERENT STYLES OF CUPOLAS. 



193 



pola is at the present time extensively used, and has many good 
points in its construction. The following history and descrip- 



FiG. 43. 




Fig 


•41- 




^ItiK 






': :::;::;;: 


— .... . ji 


^ , 


-J 


. „ 


- 4—1 - 


— -■ 






-— -■ 


_ 


- r 


~ 












- 




--■ 








- 






yjM- 


^^^ 




PAXSON HOT BLAST COLLIAU CUPOLA. SECTION OF PAXSON HOT BLAST COLLIAU 

CUPOLA. 



13 



1-94 THE CUPOLA FURNACE. 

tion of the cupola and results obtained in melting are furnished 
by his son, Victor Colliau, Detroit, Mich,, who is engaged in 
the manufacture of it. It is also manufactured with some im- 
provements, shown in Figs. 43 and 44, by J. W, Paxson & Co., 
Philadelphia, Pa., as the Paxson Hot Blast Calliau Cupola. 

Some years since, the cupola for melting iron was very in- 
complete and ineffectual — the melting of twenty-five tons at 
one heat and a rate greater than three to four tons per hour 
was unknown, and a melting of three to four pounds of iron 
with one pound of coke was considered a very satisfactory 
result. 

Large castings could not be made, and it was considered a 
large foundry that melted five to six tons per day, and later 
(only a few years ago), when large and heavy castings became 
necessary, such as anvils, steamboat bed-plates, cannon, etc., 
requiring ten, fifteen, and still later on, thirty tons at one time, 
several cupolas were used and were placed in a row, lighted at 
the same time, and when the iron in each was melted they were 
tapped simultaneously, the metal running in a common channel 
to the mould. 

All these old-fashioned cupolas consumed too much fuel in 
consequence of imperfect combustion, as was evidenced by the 
large quantity of gas burning at the top of the chimney, which 
should fiave been utilized in the melting process ; and after a 
few tons had been melted the cupola clogged with cold iron 
and slag and had to be stopped. 

I have, with my new improved patented hot blast cupola, 
surmounted all these difficulties, and am now melting sixty to 
one hundred and ten tons a day in some of them, at a speed of 
fifteen to twenty tons per hour, and ten to thirteen pounds of 
iron to the pound of coke. 

I am now building a cupola to melt twenty-five tons per hour. 

My claims are : 

1st. That the working of my new improved hot blast cupola 
has never been equaled. 

2d. A saving of from 25 to 50 per cent, of fuel. I have re- 



DIFFERENT STYLES OF CUPOLAS. I 95 

placed cupolas which were melting five pounds of iron with one 
pound of coke by one of my cupolas of the same size, and melted 
ten or twelve pounds of metal with one of coke. 

3d. Great rapidity of fusion. With the same diameter inside 
of lining of the old model, I am melting in my cupola double 
the quantity of iron per hour. 

4th. One very important feature is the saving of iron in the 
melting process. In common cupolas the loss is from 6 to 10 
per cent., in my new improved cupola 5 per cent, is the maxi- 
mum ; the loss is as low as 3^ per cent, in large meltings. 

5th. The iron melted is improved compared with the old 
system, in which the slow process of melting exposed the iron 
for too long a time to the action of the blast, which, by its 
oxidizing influences, burned the carbon combined with the iron, 
and thus lowered its grade and value. 

6th. Hot iron from the beginning to the end of the melting, 
and increasing the rapidity of the fusion as the operation ad- 
vances — for instance, on a melting of forty-seven tons of iron 
in a cupola forty-eight inches in diameter inside the lining at 
the Detroit Car Wheel Works, Detroit, the first ten tons took 
one hour and fifteen minutes to melt; the second ten tons one 
hour and ten minutes; the third ten tons one hour; the fourth 
ten tons fifty minutes, thus showing a decrease of time as the 
operation advanced — that is to say, a better working of the 
cupola at the end of the operation than at the commencement. 
This is exactly the reverse of what generally occurs in other 
cupolas. 

7th. By following my instructions, providing the quality of 
coke and iron is preserved, the same result will always be ob- 
tained ; that is to say, that with the pressure of blast indicated 
in my instructions, it will take exactly the same time to melt a 
given quantity of iron with the same proportion of fuel to the 
iron melted. 

8th. I claim that my cupola is built in the most substantial 
and workmanlike manner; that neither expense in material or 
labor is spared to make it stronger and more durable than any 
cupola hitherto constructed. 



196 THE CUPOLA FURNACE. 

9th. There is a metalHc shell surrounding the entire base, 
forming an annular air-chamber, which is provided with an in- 
let at the top, connected with the blower or fan, by means of 
which cold air is driven into the annular chamber. To compel 
a circulation of this air around the inside lining in order to take 
the caloric from it, thereby highly heating such air, and to pre- 
vent the passage of such air directly from the inlet at the top 
of the air-chamber to the outlets through the tuyeres into the 
furnace, I provide a diaphragm, the width of which equals the 
distance between the wall of the furnace and the outer shell. 
One end of this diaphragm is secured just above the inlet at the 
top of the air-chamber and extends spirally and downwardly, 
making at least one entire turn around the furnace and termi- 
nating at a point just above the tuyeres and immediately below 
the said inlet. This circulation, forced by the blower and com- 
pelled to take its course around the furnace, cools the latter, 
while the air becomes heated on reaching the tuyeres, through 
which it finds an outlet, thus performing the double function of 
cooling the furnace and supplying a hot blast. 

THE WHITING CUPOLA. 

In Fig. 45 is seen the Whiting patented cupola, designed by 
Mr. Whiting, a practical foundryman, and manufactured by 
the Whiting Foundry Equipment Co., Chicago, 111., of which 
the following description is given by them : 

The universal satisfaction given by the Whiting cupola is 
largely due to the patented arrangement and construction of 
the tuyere system, which is so designed as to distribute the 
blast most efficiently, carrying it to those portions of the cupola 
where it will do the most good, under a reduced pressure, and 
through an increased area. 

There are two rows of tuyeres. The lower ones are arranged 
to form an annular air inlet, distributing the blast continuously 
around the entire circumference of the cupola. 

This system of tuyeres is also arranged to be adjusted ver- 
tically. This provides for adjustment to the class of work, 



DIFFERENT STYLES OF CUPOLAS. 



197 



kind of fuel, and changes in the inside diameter of the cupola. 
These tuyeres are flaring in shape and admit the blast through 
a small area which is expanded into a large horizontal opening 
on the inside of the cupola, thus permitting the air to reach the 
fuel through an area nearly double that through which it enters 



Fig. 45. 




SECTION. 
(sectional view of body.) 

SECTION OF WHITING CUPOLA. 



ELEVATION. 



tTie tuyeres — admitting the same volume of blast, but softening 
its force. 

There is an upper row of tuyeres of similar construction to 
supply sufificient air to utilize to the fullest extent the escaping 
carbon gas. These tuyeres are of great service in melting and 



198 THE CUPOLA FURNACE. 

in large heats — for small heats they may be closed by means of 
our improved tuyere dampers. 

Fig. 45 represents the latest type of the Whiting patent 
cupola. A half vertical section is represented, showing the 
arrangement of the improved tuyeres and the method of adjust- 
ing them vertically. These tuyeres are arranged on slides and 
can be placed at various heights, as shown by dotted lines. 

It sometimes happens that the operator finds the cupola too 
large for his needs. When this is the case, a thicker lining can 
be used and the tuyeres adjusted accordingly, and for small 
heats the proper ratio of coke to iron can be maintained ; other- 
wise a large cupola running small heats will decrease this ratio 
materially, adding considerably to the cost of castings. 

A change can be made from coke to coal fuel, and the bed 
made of suitable depth, by simply adjusting these tuyeres. 

No other cupola has this device. It practically gives the 
operator two cupolas in one. 

This figure also shows the safety alarm attachment, side 
plates, improved blast meter and upper tuyere dampers, etc. 

Every cupola is provided with the foregoing improvements, 
together with foundation plate, bottom plate and doors, columns 
(three to five feet long), slag and tapping spouts and frames, 
peep holes with fittings, patent tuyeres and charging doors and 
frames. All fitted ready to erect. 

JUMBO CUPOLA. 

In the accompanying illustration. Fig. 46, is shown a sectional 
elevation of the large cupola known as Jumbo, in use in the 
foundry at Abendroth Bros., Port Chester, N. Y., to melt iron for 
stove plate, sinks, plumbers' fittings, soil pipe and other light 
castings, all requiring very hot fluid iron. The cupola, which 
was constructed for the purpose of melting all the iron required 
for their large foundry in one cupola, is of the following dimen- 
sions : diameter of shell at bottom to height of 24 inches, 7 feet 
6 inches ; diameter in body of cupola, 9 feet ; taper from large to 
small diameter, 5 feet 6 inches long; diameter of stack, 6 feet; 



DIFFERENT STYLES OF CUPOLAS. 1 99 

taper from cupola to stack, 6 feet long ; height from bottom 
plate to bottom of taper to stack, 20 feet ; height to bottom of 
charging doors, 18 feet; two charging doors placed in cupola 
on opposite sides. Wind box inside the shell extending around 
the cupola, 5 feet 6 inches by 9 inches wide. Height of tuyeres, 
first row, 24 inches; second row, 36 inches; third row, 48 
inches. Size of tuyeres, first row, 8x5 inches ; second row, 
6x4 inches ; third row, 2x2 inches. Number of tuyeres in 
each row, 8 ; total number of tuyeres, 24. Slag hole, 17 inches 
above iron bottom, 1 1 inches above sand bottom. Two tap 
holes. Lining, 18 inches thick; over air belt, 9 inches. Di- 
ameter of cupola at bottom, inside the lining, 4 feet 6 inches. 
Diameter above taper, 6 feet. Cupola supplied with blast by 
No. 6 Baker blower. 

It is charged as indicated in the table as follows : 



200 



THE CUPOLA FURNACE. 



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DIFFERENT STYLES OF CUPOLAS. 



20I 



, 'Three hundred and fifty pounds of limestone are . placed oixi 
each charge of iron, except the last charge, and the slag hole 
opened after the blast has been on about three-quarters of an 
hour and permitted to remain open during the rest of the heat. 

Fig. 46. 




JUMBO CUPOLA. 



The sprues, gates and foundry scrap are not milled before 
charging, and the large amount of limestone placed on each 
charge is required to liquefy the quantity of sand charged intcf 
the cupola on the scrap, and prevent clogging and bridging of 



202 



THE CUPOLA FURNACE. 



the cupola. Sixty tons of iron have been melted in this cupola 
in four hours from the time the blast was put on until the 
bottom was dropped. 

THE CRANDALL IMPROVED CUPOLA WITH JOHNSON PATENT CENTER 
BLAST TUYERE. 

In Fig. 47 is shown the above-named cupola and tuyere 
manufactured by the Foundry Outfitting Co., Detroit, Mich., 
a description of which is furnished by them as follows : 

Fig. 47. 




THE CRANDALL IMPROVED CUPOLA WITH JOHNSON 
PATENT CENTER BLAST TUYERE. 



The cupola is designed with a view of getting a more efficient 
action of the blast than is possible to attain with the methods 
now in general use. The experiments made in this new de- 
parture have finally led to a very simple and durable con- 
struction, which we place before the foundrymen and request 
that they make a thorough investigation of it. It is a well- 
known fact that the matter of forcing blast to the center of a 
cupola and obtaining a complete combustion of fuel at that 



DIFFERENT STYLES OF CUPOLAS. 203 

point, has been to many a puzzle, and various means have been 
tried to accomplish this end. But it has been found in all 
cases, that a large portion of the blast when taken in at a high 
pressure through outside tuyeres, in striking the fuel is forced 
back against the brick lining, cutting it out very rapidly just 
above the tuyeres and then escaping up along the brick wall, 
doing no good, thereby requiring a greater volume of blast to 
melt the same amount of iron than is used when the blast is 
taken in at the center of the cupola. In the illustration (Fig. 
47) is clearly shown the general arrangement. 

The air, instead of being forced into the cupola- furnace from 
the outside, is applied from the inside by means of a center 
blast tuyere attached to the under side of the bottom plate. 
This tuyere terminates at about the same height as outside 
tuyeres, and a continuous annular opening is formed for the 
blast by putting on a loose section of pipe and spacing it apart 
by means of pins that can be varied in height, so as to get any 
desired opening. On top of this loose section a cap is set ; also 
spaced apart from it by means of pins, so that a second open- 
ing is formed for the blast to enter, and by taking in more air 
at this point the carbonic oxide, which would otherwise go to 
waste, is changed into carbonic acid gas, forming the whole in- 
terior into a melting zone, insuring complete combustion. Both 
the loose pipe section and the cap can be removed to have the 
lining on them repaired. The horizontal part of the center 
blast pipe has an opening at the elbow which enables it to 
be cleaned out, in case any obstructions should fall through 
the tuyere opening above. The drop doors close over this 
tuyere and can be opened without in any way deranging it. 
No belt air-chamber is required, as the tuyere may be con- 
nected direct to the main blast pipe; but in cases where such 
air-chambers already exist, the center blast tuyere may be at- 
tached to them without in any way disarranging the blast pipe. 
We would draw special attention to the fact that but little ex- 
pense need be incurred in making this change outside of the 
price charged for the center blast tuyere and piping. 



204 



THE CUPOLA FURNACE. 



Claims are made as follows : -;• 

■ 1st. A saving in brick lining. 
2d. A saving in fuel. 

3d. More rapid melting with less volume of blast. 
4th. A more uniform temperature of iron than can be at- 
tained by the outside tuyere. 

BLAKENEY CUPOLA. 

In Fig. 48 is seen a sectional view of the Blakeney cupola 
furnace, the following history and description of which are fur- 
nished by The M. Steel Co., Springfield, Ohio. 

Fig. 48. 




SECTIONAL VIEW OF BLAKENEY CUPOLA FURNACE. 

By the Blakeney cupola furnace, the air is so distributed or 
projected into the furnace as to produce a uniform heat, giving 
the iron a uniform strength for all kinds of castings. The fea- 
tures peculiar to it are as follows : .• 

The introduction of a combination of curved tuyeres or chutes 
placed upon the wall or lining of the cupola, and forming a 
part of the wall, a proper distance from the bottom, and nearly 



DIFFERENT STYLES OF CUPOLAS. 205 

surrounding the inner and outer sides of the wall. The tuyeres 
are made of cast iron and in sections for convenience of 
handling. A blank space is left in the rear of the cupola two 
feet wide, through which the slag is blown, if required. 

A chamber or base .extending around the cupola and enclos- 
ing the space in which the air is conducted to the tuyeres. The 
bottom of this chamber, made irregular in form, hollows at 
suitable intervals to allow the metal to flow to the escape open- 
ings, in case it overflows through the tuyeres. The openings 
are closed with fusible plugs of lead or other material, to be 
melted out by the molten metal. 

The blast is conducted to this cupola through one pipe, and 
striking the blank space sidewise in rear of chamber, passes all 
around through the curved tuyeres into the center of the fur- 
nace, the blast striking into the cupola every seven-eighths of 
an inch horizontal, and 3^ inches perpendicular, or according 
to diameter of cupola. 

As a producer of a uniform grade of iron for the purpose of 
casting car-wheels, it is just what is needed for the different 
grades of iron to prevent chill cracking. 

This cupola, with its many superior advantages, has also rows 
of shelves bolted to the shell four feet apart up to the top of 
the charging door, so that it will not be necessary to tear out 
any of the lining except that which is burned out. These cu- 
polas have run eighteen months with heavy heats without being 
relined. 



These various cupolas are shown and described, not that we 
endorse all that is claimed for them, but to give our readers 
some idea of what has been done in design and construction of 
them, and what kinds may at the present time be obtained from 
cupola manufacturers. We have by no means exhausted the 
different varieties at hand, but have probably given sufficient 
examples to indicate the direction in which inventive genius has 
gone, and the objectionable points in construction which it has 
been their aim to overcome. 



CHAPTER VIII. 

ART IN MELTING. 

The melting of iron in a cupola is an art that is by many 
foundrymen and foundry foremen but little understood, and 
they never begin the melting of a heat without a dread that 
something will happen to prevent the iron being hot enough 
for the work, or that they may not be able to melt the entire 
heat. In many foundries it is almost an every-day occurrence 
to have something happen in or about the cupola to prevent 
good melting. The sand bottom cuts through, the front blows 
out, the tap hole cannot be opened without a heavy bar and 
sledge, slag flows from the tap hole with the iron and bungs 
up the spout and ladles, iron and slag get into the tuyeres, 
daubing falls off the lining and bungs up or bridges the cupola, 
stock lodges upon the lining in.settling, and only part of the 
heat can be melted. Iron melts so fast in one part of the heat 
that it cannot be taken care of; in another part it melts so 
slowly that a ladle cannot be filled before the iron is too dull 
for the work ; or, iron is not melted of an even temperature 
throughout a heat, and has to be watched in order to get 
hotiron to pour light work; the first iron is dull, or the last is 
dull, or the whole heat is dull. Some of these troubles to a 
greater or less extent occur almost daily, and it is a rare oc- 
currence in a great many foundries that a perfectly satisfactory 
heat is melted. In foundries in which these difficulties occur, 
the foundryman or his foreman, or both, do not understand 
melting. The cupola is in charge of an old professional melter 
who always ran it in this way, or a foundry laborer or helper 
has been selected for a melter and given a few instructions by 
some one who has seen a cupola prepared for a heat, or perhaps 

(206) 



ART IN MELTING. 20/ 

has melted a few heats. He is instructed until he melts a heat 
successfully, and then he "knows it all" and is left to himself, 
and perhaps he knows as much as his instructor. If he is a 
practical man, he learns the cause of all the troubles in melting 
and in time becomes a fair melter ; but at what an expense to 
his employer ! 

If he is not a practical man, he bungles along from day to 
day until he gets disgusted with his job and quits, or is dis- 
charged, and another man of the same kind is tried, with about 
the same result, for there is no one about the foundry who 
understands the art of managing a cupola to instruct him, and 
he must learn it himself or as a melter be a failure. The 
foundryman or foreman of a foundry in which this kind of melt- 
ing is done, will tell you a cupola is a very hard thing to man- 
age, and it cannot be made to melt evenly throughout a heat 
or the same every heat. If this were really the case, foundries 
making very light work, requiring hot fluid iron, would lose half 
their castings every heat or be compelled to pour large quanti- 
ties of iron into the pig bed and wait for hot iron. But this is 
not the case in stove, bench and other foundries making very 
light castings. Heats of many tons are melted every day, and 
as many pounds of iron are melted in one minute as in another 
from the beginning to the end of a heat, and there is not a 
variation of fifty degrees in the temperature of the iron from the 
first to the last tap. 

There is no chance work in nature, and there is no chance 
work in art when the scientific principles are understood and 
applied to practice, and there is no chance work in melting 
iron in a cupola when the cupola is scientifically managed, and 
there is no furnace used for melting iron more easily managed 
than the cupola furnace ; but it is necessary to understand its 
construction and mode of operation to do good melting. 

In the first place, the cupola must be properly constructed 
and of a size suitable for the amount of iron to be melted, and 
the time in which this melting is to be done. For fast melting, 
a cupola of large diameter is required, and for slow melting 



1208 THE CUPOLA FURNACE. 

one of small diameter. There are those in use at the present 
.time in vvhich'sixty tons of iron aremelted in four hours, and 
.those :in which one ton of iron is melted in four hours and a 
half, and each of these cupolas melts iron as fast as it can be 
taken care of after it is melted. The large cupola would be 
useless in one foundry, and the small one in the other. So it 
follows that a cupola must be so constructed as to be suitable 
for the- melting that it is desired to do. 

To melt iron hot and of an even temperature, the tuyeres 
must be placed low, made of a size to admit the blast freely to 
the cupola and arranged to distribute the blast evenly to the 
iuel, and the latter must be of a proper volume for the size of 
cupola. To utilize the greatest possible amount of heat from 
the fuel, the charging door should be placed high and the cu- 
pola kept filled to the door until the heat is all in. When pre- 
paring a cupola for a heat, it must be properly chipped out 
and the lining given the best possible shape for melting, by the 
application of daubing. The daubing material must be of an 
adhesive and refractory nature, and not put on so thick that it 
will fall ofif when dried or heated. The bottom door must be 
put up and supported by a sufificient number of props to make 
it rest perfectly solid against the bottom plate. The bottom 
sand must be of a quality that will not burn or be cut up by the 
molten iron, and it must be of a temper that will neither wash 
nor cause the iron to boil. It must be carefully packed around 
the edges and rammed evenly, and no harder than the sand for 
a mould, and given a proper pitch to cause the iron to flow to 
the tap hole as fast as melted. A front and spout lining mate- 
rial must be selected or prepared that will not cut or melt. And 
the front must be put in solid with a proper sized tap hole, 
^nd the spout given the right shape and pitch. The cupola 
having been thus prepared, it is ready for melting. Shavings 
and wood are put in for lighting the melting fuel or bed, and a 
sufificient quantity of coal or coke is put in to fill the cupola to 
the top of the melting zone after it has settled. As soon as 
this fuel is well on fire and the heavy smoke is burned off so 



ART IN MELTING. 209 

that the top of the bed can be seen, it is leveled up with a few 
shovelfuls of fuel, and charges of iron and fuel are put in until 
the cupola is filled to the door. The weight of the bed fuel, 
and charges of iron and fuel, must be learned for each cupola, 
for scarcely any two are charged exactly alike. 

It will thus be seen that the melting of iron in a cupola is 
very simple. But all these things and many more must be 
learned and practiced to make it so, and they cannot be learned 
in one or in a dozen heats. Slag and cinder adhere to the lin- 
ing at one point to-day and at another to-morrow, and the 
chipping out must be different. The lining is burned away 
more at one point to-day than it was yesterday. A new lining 
requires a different shaping than an old one, as a lining burns 
out and the diameter of the cupola increases. More fuel is re- 
quired for a bed, and the weight of charges of fuel and iron 
must be increased. All brick are not suitable for a cupola lin- 
ing, and a good brick may be laid up in such a way that a 
lining will not last half so long as it would do if properly put 
in. All daubing material is not suitable for repairing the lin- 
ing of a cupola, and the best daubing is worthless when not 
properly applied. Bottom sand when used over and over again 
becomes worthless, and all sands are not suitable for a bottom. 
The front may be put in with material that melts, and the tap 
hole cannot be kept open and free of slag; or the front made 
of a shape that iron chills in the tap hole between taps. The 
spout lining material may not be suitable, and may melt and 
bung up the spout with slag, or the lining may be made of a 
shape that two or three ladles are required to catch the many 
streams that fall from it at the same time. 

To learn to manage a cupola perfectly, a close study of all 
the materials used in melting and their application to melting 
are necessary, and months of careful observation are required 
to learn them, but by an intelligent man they can be learned. 
A moulder, when serving his time as an apprentice, is seldom 
given an opportunity to learn melting, and when he becomes 
foreman of a foundry knows nothing whatever about the man- 
14 



210 THE CUPOLA FURNACE. 

agement of a cupola and is completely at the mercy of the 
melter. The time has passed in many localities when the entire 
force employed in a foundry was subject to the whims of a 
melter and compelled to take a day off whenever he did not 
see fit to work, and a foreman who does not fully understand 
the management of cupolas is no longer considered a com- 
petent man to have charge of a foundry. It should be the aim 
of every moulder who aspires to be a foreman or foundryman 
to learn melting, and when he takes charge of a foundry he 
should at once learn all the peculiarities of the cupolas of that 
foundry, and be able to run off a heat as well as the melter, or 
instruct the melter how to do it. In conversing with foremen, 
we have frequently remarked to them that the foreman of a 
foundry should be the melter, and many of them have replied 
that they would give up the foremanship before they would do 
the melting. To be a melter does not imply that the melter 
should perform the labor requisite to melting, for a melter may 
direct the melting of a heat without ever touching the iron to 
be melted or any of the material required to melt it. By going 
inside for a few minutes and giving directions how it must be 
done, any intelligent man can be employed to do the work, 
and he can be instructed from the charging door how to pick 
out and daub a cupola or repair a lining. He can be shown 
how to put up the doors and support them in place; how to 
prepare daubing, front and spout material, select and temper 
bottom sand, and instructed from the charging door and front, 
how to put in a bottom front and spout lining ; how to light 
up and burn the bed, and given a slate of charges and direc- 
tions for putting them in the cupola. After he has been di- 
rected by a competent melter in this way for a few heats, it is 
only necessary for the melter or instructor to inspect his work 
from time to time, to see that it is properly done and prevent 
the lining getting out of shape or other things occurring, in 
which a new melter cannot be instructed in a few days ; and his 
work should be inspected to prevent him getting into a rut, as 
melters so frequently do when left to themselves. 



CHAPTER IX. 

SCALES AND THEIR USE. 

There is nothing more essential to the good melting and 
mixing of iron, than an accurate weighing scale upon the 
scaffold near the cupola charging door. The best for this pur- 
pose are the platform scales mounted on large wheels, with the 
platform about two feet above the floor or on a level with the 
charging door. For foundries that make a large quantity of 
gates, sprews and light scrap to be remelted, an iron box made 
of boiler plate and open at one end for shoveling out iron and 
fuel should be placed upon the scales. A one or two ton scale 
is sufficient for charging almost any cupola, for the iron and 
fuel are weighed in charges or drafts that seldom exceed this 
weight, and when large pieces are charged they are generally 
weighed on the scales in the yard. Scales placed in the floor 
on the scaffold upon which barrows of iron and fuel are weighed 
as they are brought on the scaffold, give the weight of the 
stock used, but they are of no value in dividing it into charges 
if the stock is not charged direct from the barrows into the 
cupola, which is seldom done. 

The melting of iron in a cupola, when reduced to an art, con- 
sists in melting the greatest possible amount with a given 
amount of fuel ; and this can only be done by first learning the 
amount of iron that can be melted with each pound of fuel, and 
placing that amount upon the fuel in the cupola at the proper 
place to be melted. If all the fuel required to melt ten or 
twenty tons of iron were first placed in a cupola and all the 
iron put upon it in one lot, it would be so high above the melt- 
ing zone that none of it could be melted until fully one-half of 
the fuel had been burned away and the iron permitted to settle 

(211) 



212 THE CUPOLA FURNACE. 

to the melting zone, in which case all the fuel consumed before 
melting began would be wasted, and the iron would not have a 
sufificient amount of fuel to melt it. 

For this reason the fuel and iron are divided into charges and 
placed in a cupola in layers, each layer of fuel being only sufili- 
cient to melt the layer of iron placed upon it, when it descends 
into the melting zone. If the charge of fuel be too heavy, the 
excess must be consumed before the iron can be melted by it; 
and if the charge of iron be too heavy, all of it cannot be prop- 
erly melted with the charge of fuel. It is, therefore, necessary 
that the layers of fuel and iron should be of exactly proper pro- 
portions to do economical melting. 

There are many foundrymen who do not understand this 
theory of melting, but think fuel placed in a cupola melts iron 
no matter how it is put in, and trust to their melter to guess 
the weight of fuel consumed and iron melted in an entire heat. 
Others have the fuel and iron weighed in the yard or upon the 
scales placed in the floor of the scafTold, and permit the melter 
to guess the respective weights of fuel and iron in charging. 
In the first case an excess of fuel is always consumed, the 
melting is slow and the amount of iron charged is often more 
than required to pour off the work ; or it is insufficient, and more 
iron has to be charged after the stock is low in the cupola, and 
the destruction of cupola lining is greater than if the iron had 
been charged at the proper time. In the second case the melt- 
ing is irregular, and the temperature of the iron uneven, even if 
only a proper amount of iron and fuel to melt it is placed upon 
the scaffold, for the melter cannot in charging divide it evenly. 
No melter can guess the weight of a promiscuous lot of scrap, 
sprews, gates, etc., or accurately estimate the weight of pig 
iron by counting the pigs. The counting of shovels, riddles or 
baskets of fuel in charging is the greatest fallacy of all ; for 
riddles and baskets always hold more the longer they are in 
use, and shovels hold less. The melter makes no allowance for 
the increase in size of riddles or baskets, but always puts in a 
few extra shovelfuls to make up for reduced size of the shovel, 



SCALES AND THEIR USE. 213 

as it wears down. Even when these articles are new, a few 
pounds more or less may be put on, so that it is simply guess- 
work at best. 

Placing upon a scaffold old worn-out scales that are unfit for 
use in other parts of the works and frequently only weigh 
correctly on one side or end, is a mistaken economy frequently 
practiced by foundrymen. The weighing of cupola stock upon 
such scales is only guess-work, and the saving in fuel and im- 
provement in melting would soon pay the cost of accurate scales. 



CHAPTER X. 

THE CUPOLA ACCOUNTS. 

In all well regulated foundries a cupola account of melting 
is kept and an accurate record made of each heat, and pre- 
served for future reference. In this way, the melting is re- 
duced to a system and the foundryman knows what is being 
done in his cupola each day and is able to make an estimate 
of the cost of melting. These records are also of value in 
showing the amount of fuel required for a bed and in charges 
when the cupola is newly lined, and the amount they should be 
increased as the lining burns out and the cupola is enlarged. 
Mixtures of various brands and grades of iron are recorded, 
with the result of the mixtures upon the quality of castings, and 
a great deal of experimental work in melting and mixing of 
irons is saved and better results are thus obtained. The 
manner of keeping these accounts varies in different foundries. 
In some they are kept very simply, showing only the amount 
of fuel and iron in each charge and total fuel consumed, iron 
melted, and time required in melting. Others show kind and 
amount of fuel used, in bed and charges, and amount of each 
brand or quality of iron placed in charges, total amount 
melted, time of lighting up, time of charging, putting on blast, 
first iron melted, blast off, pressure of blast, etc. 

Others are still more elaborate, and not only show all the de- 
tails of the cupola management, but also a report presenting 
cost of various castings produced, good and bad, the cost of 
the bad ones being charged to the good ones made off the 
same pattern or for the same order, and the average found. 

To give foundrymen who have never used such reports an 
idea of how they are made out, we here give a few blank re- 
ports from leading foundries. That of Abendroth Brothers, 
Port Chester, N. Y., and Byram & Co., is filled in to show the 
manner of placing the various items in the blank report. 

(214) 



THE CUPOLA ACCOUNTS. 



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THE CUPOLA FURNACE. 

BYRAM & COMPANY, 



IRON WORKS. 



435 and 437 Guoin Street 
46 and 48 Wight Street. 



DETROIT, MICH. 

FUEL USED and IRON MELTED at the Foundry of 



IN THE COLLI AU CUPOLA 
FURNACE. 



CHARGES. 



Diameter Inside of Lining 54 ins 

Pressure of Blast oz 

Lighting, 

Loading Commenced, i 
Blasting, - 2 

Closed Tap Hole, 
First Iron Taken, 
Loading Finished, 
Blasting Stopped, 
Dropped Bottom, 




REMARKS:. 



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No. 



THE CUPOLA ACCOUNTS. 



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THE CUPOLA ACCOUNTS. 221 

The blanks for these reports and records of them are fur- 
nished to the foundry foreman or melter, and preserved in dif- 
ferent ways. In some foundries they are furnished in separate 
sheets, and when filled out and returned are kept in files pro- 
vided for the purpose. In other foundries they are made out 
in book form and filled in by the foreman or foundry clerk. 
Such reports can be kept by a foundry foreman when provided 
with a small ofifice for doing such work ; but when there is no 
office, as is frequently the case, a report book kept by the fore- 
man soon becomes so soiled that it is useless for reference, and 
report blanks are generally furnished in separate sheets and 
either filed or transferred to the report book by the foundry 
clerk. When only a record of fuel used and iron melted is kept, 
the report is generally made on a slate upon which lines are 
scratched similar to those in a printed report, and name and 
amount of various grades of iron and fuel filled in with the 
slate pencil. The fuel to be used and amounts of various irons 
to be melted in each charge are placed upon the slate by the 
foreman and given to the melter to charge the cupola by, and 
after the heat is melted the slate is sent to the foundry office to 
be copied into the cupola account book. This latter is the 
oldest way of making out these reports. 

A cupola account is of no value if not correctly kept, and it 
should be the aim of every foundry foreman to see that the re- 
port he makes of fuel consumed and iron melted is correct, and 
not, as is frequently done, endeavor to make a good showing for 
himself, of melting a large per cent, of iron with a small per 
cent, of fuel, and permit his melter to shovel in extra fuel to 
make iron sufficiently hot to run the work. Foundrymen can 
readily ascertain the amount of fuel consumed by comparing 
the amount reported with the amount purchased. False reports 
only reduce the foreman in the estimation of his employers, 
and are frequently the cause of his losing his position. 



CHAPTER XL 

PIG MOULD FOR OVER IRON. 

In foundries in which the iron is all poured from hand ladles, 
there is frequently a small amount of iron left in a ladle that is 
not sufficient to pour a mold, and cannot be used except when 
the iron is very hot and the moulder catches in immediately 
after pouring. 

Moulders will not take the time to carry this iron back to 
the pig bed at the cupola, and it is generally poured upon the 
floor in the gangway or into the sand heaps ; and a great deal 
of light scrap is in this way made in large foundries, that re- 
quires much time and labor to collect and even when carefully 
collected with much loss in the sand and gangway dirt. To 
obviate this wastage of iron and labor, many foundries have 
Fig. 49. adopted the cast iron pig mould 

shown in Fig. 49, and placed one 
of them in the gangway at the 
head of each floor, or at conveni- 
ent distances apart in the gang- 
piG MOULD FOR OVER IRON. ^gyg f^j- ^^c mouldcrs. All thc 

over iron is poured into these moulds and is collected in a pig 
of convenient size for handling and melting, greatly reducing 
the loss of iron and cost of removing. 

( 222 ) 




CHAPTER XII. 

WHAT A CUPOLA WILL MELT. 

The cupola furnace was originally designed for melting cast 
iron for foundry castings, and at the present time is principally 
employed for that purpose, but it is now also used in the melt- 
ing of almost all of the various grades of manufactured iron 
and steel, and many other metals. 

It is extensively employed in the melting of pig iron in the 
manufacture of Bessemer steel, and in the melting of iron for 
castings to be converted into steel and malleable castings after 
they are cast. It is also used in melting steel for steel cast- 
ings, but as it makes an uncertain grade of steel is only em- 
ployed for the more common grade of castings. 

It is also employed in melting tin plate scrap, sheet iron, 
wrought iron and steel wire, gas pipe, bar iron, horse shoes and 
all the various grades of malleable wrought and steel scrap, 
found in a promiscuous pile of light scrap and used in the 
manufacture of sash, elevator and other weights, and melts them 
readily, producing a very hot fluid metal, and when properly 
managed is the very best furnace for this purpose. 

It is to some extent used in the smelting of copper ores and 
the melting of copper, in the manufacture of brass, and also in 
the melting of brass for large castings ; but in melting brass, 
the alloy is oxidized to so great an extent that an inferior 
quality of brass is produced to that obtained from crucibles. 

Lead is frequently melted in cupolas. It melts more slowly 
than would naturally be expected, and it is very difiEicult to re- 
tain it in a cupola in the molten state, as it is almost impossible 

("223 ) 



224 THE CUPOLA FURNACE. 

to put in a front through which it will not leak, and the ladle is 
generally heated and the tap hole left open. 

The quantity of cast iron that can be melted in a cupola per 
hour depends upon the diameter and height of cupola, and at 
the present time varies from one hundred pounds to hundreds 
of tons. The number of hours a cupola will melt iron freely 
when properly managed, is only limited by the length of time 
the lining will last. Cupolas have been run continuously from 
one o'clock Monday morning until twelve o'clock Saturday 
noon, melting fourteen tons per hour. 

The size and weight of a piece of cast-iron that can be melted 
in a cupola at one heat, depends upon the size of the cupola. 

As a rule, any piece of iron that can be properly charged in 
a cupola can be melted. In steel-works cupolas, ingot moulds 
weighing five tons, are melted with ease in the regular charges 
of the cupola. 

At the foundry of the Pratt & Whitney Co., Hartford, Conn., 
a large charging opening is placed in the cupola for the purpose 
of charging large pieces of iron to be melted, and almost any 
piece can be melted in one heat that can be placed in the cupola. 

At the foundry of the Lobdell Car Wheel Co., Wilmington, 
Del., an oblong cupola with charging door placed at the ends 
was constructed shortly after the War of the Rebellion to melt 
cannon and other heavy government scrap, and large cannon 
weighing many tons were melted in this cupola without previ- 
ously breaking them up. 



CHAPTER XIII. 

MELTING TIN PLATE SCRAP IN A CUPOLA. 

Tin plate scrap is melted in the ordinary foundry cupola the 
same as cast iron scrap, but more fuel is required to melt it. 
The best results are obtained with i pound of coke to from 3 
to 4 pounds of scrap and a mild or light blast. Various ways of 
preparing the scrap for charging, such as hammering or press- 
ing it into ingots and forming it into compact balls, have been 
tried ; but as good results are obtained by charging it in bulk, 
and it is generally added in this way. The charges are made 
of about the same weight as charges of iron in a cupola of 
similar size, but more fuel is added. The scrap when first put 
in the cupola is very bulky and takes up a good deal of room, 
but when heated it settles down into a compact mass, and takes 
up very little more space than a charge of cast iron scrap. 
Tin plate scrap settles rapidly, but melts slower than cast iron 
scrap or pig. 

Numerous attempts have been made to recover the tin de- 
posited upon the iron by heating the scrap in various ways to 
a temperature at which tin melts, but the coating of tin is so 
light it will not flow from the iron. All such attempts to re- 
cover it have proved failures. The iron, or rather steel, which 
is coated with tin is a very soft and tough material, but when 
melted the tin alloys with it, and the metal produced is very 
hard and brittle. The molten metal from this scrap has very 
little life, chills rapidly in the spout, ladles or molds, must be 
at a white heat when drawn from the cupola, and must be 
poured as quickly as possible. When not melted extremely 
hot the metal expands or swells in cooling to so great an ex- 
tent as to tear a sand mold to pieces or break an iron mold 
15 (225) 



226 THE CUPOLA FURNACE. 

where it cannot escape. When the metal is melted very hot 
this expansion does not take place to so great an extent, and a 
sand or iron mold may be used for any work into which it is 
to be cast. 

The molten metal is more susceptible to the effect of mois- 
ture than iron, and is instantly thrown out of a mold when 
sand is worked too wet and cannot be made to lay in it. The 
sand must, therefore, be worked as dry as possible. The metal 
is very hard and brittle, and only fit for sash and other weights, 
and even these when light and long must be handled with care 
to avoid breaking. The weights when rough cannot be chipped 
or filed smooth, and sash weights made of this metal are gen- 
erally sold at a less price than iron weights ; for when rough 
they wear out very quickly the wooden box in which they are 
hung, and builders dislike to use them. A foundryman who 
recently had a contract from the Government for a number of 
weights of several tons each, to be used for holding buoys in 
the ocean, made them from tin plate scrap. When cast they 
were so rough that he remarked it was a good thing they were 
to be sunk in the mud under the ocean, for they were not fit to 
be seen. 

In a number of experiments we made in melting this scrap, 
we found we could produce a gray metal from it about as hard 
as No. 3 pig iron, by melting it with a large per cent, of fuel 
and a very light blast. But the metal was very rotten and had 
little if any more strength than when white. We tried a number 
of experiments to increase its strength, but in none of them did 
we succeed to any extent. Melting it very hot and running it 
into pigs and remelting the pig improved the strength in some 
degree; but this was expensive, and the results did not justify 
the expense. We also made a number of tests to learn the 
amount of metal lost in melting this scrap, and found with a 
light or proper amount of blast to do good melting there was 
practically no loss. With a strong blast the loss was heavier, 
and in one heat, with a very heavy blast, we lost lo per cent, of 
the metal charged. The metal from this heat was a little 



MELTING TIN PLATE SCRAP IN A CUPOLA. 227 

stronger and also a little harder, which was probably due to 
oxidation of the tin and iron by the strong blast before melting. 
In melting old roofing tin, rusted scrap and old cans, the loss 
in melting varied from lO to 25 per cent,, which was probably 
due to rust, paint and solder used in putting the work together. 

Tin acts as a flux when melted with iron, and renders it more 
fusible. Scrap from which the tin has been removed by acids 
to recover the tin or by the process employed in the manu- 
facture of chloride of tin, is more difftcult to melt in a cupola 
than when covered with tin, and more fuel and time are re- 
quired to melt it, but a better grade of iron is produced from it. 
Scrap of this sort should be melted soon after the tin is removed 
from it, for it rusts very quickly, and when rusted to any extent 
produces nothing but slag when melted. 

Scrap sheet iron is more difficult to melt than tinned scrap 
and is seldom melted in a cupola, for better prices are paid for 
it by rolling mills than foundrymen can afTord to ofTer. 

Galvanized sheet-iron scrap cannot be melted at all in a cu- 
pola in large quantities, for the zinc used in galvanizing it, 
acting like the zinc solution used in the Babcock fire extin- 
guishers, cools the fire in the cupola to a marked degree. When 
melting tinned scrap any galvanized scrap that has been mixed 
with it must be carefully picked out, for even in small quanti- 
ties it lowers the heat in a cupola to such an extent that the 
metal from the tinned scrap cannot be used, and must be poured 
into the pig bed if it runs from the cupola at all. There are a 
number of ways of doctoring the metal from tin-plate scrap 
when it melts or fiows badly, by the use of gas and oil, retort 
carbon, etc., but they do not improve the quality of the metal 
to any extent, and it is very doubtful if they increase its melt- 
ing or flowing properties. 

A cupola of any suitable size can be employed for melting 
tin-plate scrap and an entire heat of the scrap may be melted 
alone, or it may be mixed with cast iron scrap or pig, and 
melted, or again, it may be melted alone directly after a heat 
of iron. It is a common practice in many small foundries to 



228 THE CUPOLA FURNACE. 

melt this scrap in the cupola for sash and other weights 
directly after melting a heat of iron for soft castings. An extra 
heavy charge of fuel is placed upon the last charge of iron to 
check the melting for a few minutes by preventing the scrap 
settling into the melting zone, and the soft iron is all melted and 
drawn ofT before the scrap begins to come down. In melting 
long heats of this scrap it is necessary to flux the cupola with 
limestone or shells in sufficient quantities to produce a fluid 
slag. The flux should be put in on the first charge of scrap in 
very small cupolas and on the second or third charge in large 
cupolas, and on each charge throughout the heat afterward. The 
slag hole should be placed at the lowest point consistent with 
the amount of molten metal to be collected in the cupola at one 
time, and opened as soon as the first charge of scrap, upon 
which flux is placed, has melted. The slag hole may be 
opened and closed from time to time, but it is better not to 
make the hole too large, and leave it open throughout the heat. 
The flow of slag then regulates itself and there is no danger of 
it running into the tuyeres. In melting a few hundredweight 
of this scrap in a cupola, after melting a small heat of iron, it 
is not necessary to charge flux in sufficient quantities to pro- 
duce a fluid slag to be tapped, unless the cupola is very small 
and shows signs of bunging up. In this case flux must be 
charged with the iron, and slag tapped early in the heat, to 
keep the cupola in condition to melt the scrap after the iron is 
melted. 

When constructing a cupola expressly for melting tin-plate 
scrap the charging door or opening should be placed about 6 
inches above the scafTold floor, so the scrap may be dumped in 
from a barrow and save handling it a second time with forks. 
The charging door should be much larger than in a cupola of 
the same diameter for melting iron and should be not less than 
3 or 4 feet square in any case, and for cupolas of very large in- 
side diameter the opening should be equal to one-half or three- 
fifths the diameter of the shell, and 4 or 5 feet high. The 
height of the door above the bottom depends upon the 



MELTING TIN PLATE SCRAP IN A CUPOLA. 229 

diameter of the cupola, In large cupolas it should be placed 
1 8 or 20 feet above the bottom and in smaller cupolas as high 
as possible without danger of the stock hanging up in the 
cupola before settling into the melting zone. The lining 
material must be carefully selected, for a poor fire brick will 
not last at the melting zone through one long heat; in fact, 
none of the fire brick lasts very long at this point and it is gen- 
erally necessary to put in a few new ones after each heat. 
High silicon brick is said to last better than any other brick, 
but some of the native stone linings which we have described 
last longer in melting this scrap than any of the fire brick, and 
they are generally used for lining cupolas for this work. The 
cost of melting tin-plate scrap in a cupola is from $1 to $2 per 
ton more than the cost of melting iron. The amount of profit 
in melting this scrap for weights, &c., depends, like all other 
foundry business, upon the location and size of the plant and 
the management of the business ; but at the present time, even 
under favorable circumstances, the profits are small. 



CHAPTER XIV. 

COST OF MELTING. 

There is probably less known about the actual cost of melt- 
ing iron in cupolas for foundry work than about any other 
branch of the foundry business. But few foundrymen make' 
any attempt at keeping a cupola or melting account. Many of 
those who do, keep it in such a way that they not only fail to 
learn the cost of melting, but are misled by the account to 
suppose their melting costs them a great deal less per ton than 
it really does. In the majority of foundries the melting is left 
entirely in the hands of the melter, who as a rule has no system 
for doing the work, and has no control over his assistants or in- 
terest in having them do a fair day's work. In many of the 
foundries we visit, twice the number of men are employed as 
cupolamen as are employed in melting the same amount of iron 
in other foundries, where the facilities for handling the stock 
are almost the same, and the expense of lining and daubing 
material is frequently double with one melter what it is with 
another in the same sized cupola with the same sized heats. 

In many foundries the fuel is not weighed, but is measured 
in baskets, or the number of shovels counted and the weight 
estimated. When the fuel is measured in baskets, the baskets 
always stretch and enlarge, and an old basket frequently holds 
one-third more than a new one; from lo to 20 pounds more 
can easily be piled on the top of a basket after it is filled. 
Foundrymen who charge their fuel by the basket always use 
more fuel than they estimate they are using; when the shovels 
are counted, each shovel may be made to weigh more than is 
estimated, and a few extra shovelfuls are always thrown in, for 
fear some were not full. When too much fuel is used in a cu- 

( 230) 



COST OF MELTING. 23 I 

pola there is not only a wastage of fuel, but there is slow melt- 
ing, increased destruction of the lining, and an increased wear 
and tear of the blast machinery. For these reasons every 
pound of fuel that goes into the cupola should be accurately 
weighed. Even when the fuel is supposed to be accurately 
weighed, there should be some check on the melter, for he will 
shovel in extra fuel if not watched. 

At a foundry we recently visited in New Jersey an accurate 
account of the melting had been kept for a year ; at the end 
of the year the president of the company had figured up the 
amount of fuel consumed in the cupola and compared it with 
the amount purchased, and found they were short 260 tons. 
At another foundry, where the melter always reported melting 
7 pounds of iron to i pound of anthracite coal, they ran short 
300 tons in a year. This kind of work should be prevented by 
checking up the melter's report and comparing it with each 
car-load of fuel consumed. 

A cupola book should be provided, with blank spaces for re- 
cording the weight of coal or coke in the bed and charges, and 
the weight of each brand of iron. No. 1,2 or 3 and scrap, show- 
ing the exact mixture of each charge and heat. A note should 
also be made of the quality of iron produced from the mixture. 
Such a record is of great value in making mixtures and charg- 
ing a cupola, if it is properly kept. 

The cost of melting per ton is figured in a number of differ- 
ent ways, but to be of any practical value the entire cost of 
melting should be figured on as follows : 

Interest on cost of cupola plant and depreciation in value of 
same. 

Fire brick for relining and repairs. 

Fire clay, loam and sand for cupola and ladles. 

Repairs to cupola, blast pipe, elevator, scaffold, runway, 
blower, &c. 

Belts, oil, &c., for blower. 

One-fourth the entire cost of engine. 

Tools, wheelbarrows, buckets, hose, shovels, forks, rakes, 
hoes, sledges, picks, bars, trowels, bod sticks, tap bars, &c. 



232 THE CUPOLA FURNACE, 

Wood for lighting up and drying ladles. 

Coal or coke consumed in melting. 

Labor employed in removing the dump, making up cupola, 
milling dump and gates, collecting gates, scrap and bad cast- 
ing from foundry, placing iron and fuel on scafifold, charging, 
breaking and piling iron in yard, breaking up bad castings, 
daubing ladles, &c. 

When the cost of all these items has been learned, and the 
amount divided by the number of tons melted, it will be found 
that the cost of melting is about $2 per net ton of iron in the 
ladles. In foundries with all the modern improvements for 
handling the stock the cost is a little less than $2 per ton, and 
in foundries with none of the improvements for handling the 
stock and no system in melting, the cost per ton is as high as 
$3. When there is doubt as to the accuracy of weights in 
charging, the weights should be compared with the fuel pur- 
chased and castings sold, and the cost of melting may be 
figured on the weight of castings sold in the place of the 
amount of iron melted. To make a cupola report of value, the 
fuel, labor and tool accounts should be kept separate, and an 
effort made to reduce the expense of each account. 



CHAPTER XV. 

EXAMPLES OF BAD MELTING. 

Much has been written and published on melting by foundry- 
men and foundry foremen, who invariably give an account of 
rapid or economical melting done in their foundries ; and it is 
seldom, if ever, that they publish accounts of poor melting or 
poor heats melted by bad management of their cupolas, or in 
their attempts to reach that perfection in melting of which they 
write. In giving points on melting for the benefit of others, it 
is as essential that causes of poor melting should be known 
that they may be avoided, as it is that those essential to good 
melting should be known that they may be practiced, and we 
therefore present a few instances of poor melting that have 
come under our observation in foundries we have visited, or in 
which we have been called upon to render assistance to over- 
come troubles in melting which were both annoying and 
expensive. In these instances we only give examples of 
what may occur in any foundry, and has occurred in many 
of them, where foundrymen are wholly dependent on their 
melters. 

In 1878 we were engaged in making some experiments in 
melting with oil at the stove foundry of Perry & Co., Sing Sing, 
N. Y., at that time the largest stove works in the country. 
They were melting from 50 to 60 tons per day in four cupolas 
entirely with convict labor, and the results in melting were very 
unsatisfactory. Mr. Andrew Dickey, one of the firm and man- 
ager of the works, came to us one day after some very bad 
heats and asked us to take charge of their cupolas, set our own 
wages, and carry on our experiments at the same time. We 

( 233 ) 



I 



234 THE CUPOLA FURNACE. 

took charge of their cupolas the following day and soon had 
their melting going along smoothly, but we did not like the job, 
and suggested to Mr. Dickey that we should teach a man to 
melt who could take our place when we were ready to leave, 
and this he consented to do. A man was selected who proved 
an apt scholar, and we soon had him instructed in all the details 
of melting, and when we left he took full charge of the cupolas. 
Two years later we received a despatch from Perry & Co., 
stating that they wished to see us as soon as possible at their 
Sing Sing Works. Upon our arrival there late in the afternoon, 
Mr. Dickey informed us they were having trouble with all their 
cupolas, and it had been impossible of late to get a good heat 
out of any of them, and wished us to see what was the trouble. 
We found the same man in charge whom we had two years pre- 
viously taught to melt, and inquired of him what the trouble 
was. He said he did not know, that he had fully followed our 
instructions and had no trouble in melting until within the last 
few weeks; during this time the cupolas had been melting 
very badly. He had increased and decreased the fuel in the 
bed and charges, increased it in one part of the heat and de- 
creased it in another, varied the amount of iron on the bed and 
in the charges, but had been unable to locate the trouble. We 
asked him to describe how the cupolas melted, and he said they 
melted the first few tons, which was about the first two charges, 
fast and hot; after that the melting gradually grew slower until 
near the end of the heat, when melting almost ceased ; the cu- 
polas were so bunged up every heat that they could scarcely be 
dumped, and it was only after a great deal of labor with bars 
that a hole could be gotten through, so that they would cool off 
by the next morning. The iron was of an uneven temperature, 
frequently too dull for pouring and in some parts of the heat 
white hard, although nothing but soft iron had been charged. 
He thought the trouble must be in the blast — that old " no 
blast" story that foundrymen hear so often, when melters do 
not know how to manage a cupola and have to lay the blame 
on something. We informed him that the trouble could not be 



EXAMPLES OF BAD MELTING 



235 



Fig. 50. 




SECTIONAL VIEW LINING OUT OF SHAPE. NO. I. 



236 THE CUPOLA FURNACE. 

in the blast, or the cupolas would not have melted the first two 
charges fast and hot ; that the trouble was the stock logged in, 
settled or settled unevenly after melting the first two charges, 
which was the cause of the uneven melting in the latter part of 
the heat, and he must have permitted the linings to get into a 
shape that produced this condition in the cupolas. He did not 
think this possible, for he had followed our directions for shap- 
ing a lining, but admitted that he frequently found pieces of 
unmelted pig and scrap in the cinder above the tuyeres when 
chipping out, which confirmed our theory, and we looked no 
further for the cause of poor melting. 

The following morning the cupolas were almost closed up 
with cinder slag and iron, and after a great deal of labor in 
breaking down and chipping out we found the linings in the 
shapes shown in Figs. 50 to 53, 

Cupola No. T had not been lined for a long time, and the lin- 
ing was burned away until it was very thin all the way up. 
This did not prevent the cupola melting, but should have made 
it melt faster; for as a cupola is enlarged in diameter by burn- 
ing out of the lining its melting capacity increases; but in this 
case the melter had permitted the lining to become hollow 
around the cupola just above the tuyeres. When the stock 
settled, that on the outer edges logged in this hollow, became 
chilled and threw the blast to the centre of the cupola. After 
a few tons had been melted the chilled stock over the tuyeres 
increased rapidly until the melting was restricted to an open- 
ing in the centre, which gradually closed up with the fan blast, 
and the longer the cupola was run the slower it melted, until 
melting ceased altogether. 

In No. 2 the lining was not burned away to so great an ex- 
tent as in No. i, but the melter had permitted it as in No. i to 
become hollow over the tuyeres. He had been troubled with 
molten iron running into the tuyeres, and to prevent it doing 
so had built the lining out from 3 to 4 inches with daubing over 
each tuyere. This cupola like the others was 60 inches in di- 
ameter with six oval tuyeres each 4 by 12 inches laid flat. Over 



EXAMPLES OF BAD MELTING. 
Fig. 51. 






iE 






n 



237 



SECTIONAL VIEW LINING OUT OF SHAPE. NO. 2. 



238 THE CUPOLA FURNACE. 

each of these tuyeres was a projecting hump 3 to 4 inches thick 
and 16 to 18 inches long; add to the thickness of these humps a 
hollow in the lining of 4 to 6 inches and a shelf from 8 to 10 
inches wide was formed over each tuyere upon which the stock 
could not help lodging, and could not be melted after lodging. 
When the cupola was first put in blast it melted very well, but 
after the stock began to lodge gradually, melted more slowly 
until it finally bunged up. The convict who had charge of this 
cupola informed me that every day, when chipping out, he found 
pieces of pig iron and unburned coke lodged over the tuyeres, 
and molten iron frequently ran into the tuyeres when melting. 
To prevent this, he had gradually built the lining out over the 
tuyeres (from day to day), until the shape we have described 
was reached ; but it neither prevented the stock lodging nor 
the molten iron flowing into the tuyeres, but increased the 
trouble. 

No. 3 (Fig. 52) had recently been newly lined, and melted dif- 
ferently from the other two cupolas. It was in a better shape over 
the tuyeres, and the trouble in melting was not caused by the 
hanging up of the stock from lodgment over the tuyeres, but 
by the escape of blast around the lining. The cupola had been 
lined with 9 inch brick and its diameter greatly reduced by the 
heavy lining, and as a result the cupola melted more slowly 
than with the old lining. To make it melt faster, the melter 
had chipped it out very close every day and permitted the 
lining to burn out to enlarge the cupola at the melting point. 
This would have improved the melting had the belly in the 
lining been given a proper shape ; but no attempt had been 
made to shape it, and the lining was burnt out to a depth of 
from 4 to 6 inches with a sudden ofTset from the small to the 
large diameter. The stock did not expand in settling to fill 
this sudden enlargement, and a large part of the blast escaped 
into the belly and re-entered the stock above the melting zone. 
This naturally threw the heat against the lining at the top of 
the belly and cut it out very rapidly, and would have ruined 
the lining in a week's time had the cupola been permitted ta 



EXAMPLES OF BAD MELTING. 

Fig. 52. 




a 




239 



SECTIONAL VIEW LINING OUT OF SHAPE. NO. 3. 



240 THE CUPOLA FURNACE. 

continue to work in this way. The belly in the lining was filled 
with stock when charging, and the melting was very good until 
the stock settled and the blast began to escape in the manner 
described, when it rapidly grew slower until it stopped alto- 
gether, and this cupola which had been relined to make it melt 
better was the poorest melting one of the lot. 

In Fig. 53 the lining had been permitted to belly out over the 
tuyeres at a very low point and a shelf formed, upon which the 
stock lodged by building the lining out over the tuyeres, but the 
humps over the tuyeres were not so long as those in Fig. 51, 
and the stock had settled between the tuyeres to a greater ex- 
tent than over them. This uneven settling of the stock had 
thrown the heat against the lining at different points and burnt 
it out in holes all the way up to the charging door. 

Here were four cupolas, all of the same diameter, having the 
same number of tuyeres, with the lining of each one in a dif- 
ferent shape, but all having the same objectionable feature — a 
hollow in the lining over the tuyeres, which was the real cause 
of bad melting. We had all the humps over the tuyeres chipped 
off and the linings daubed up perfectly straight for six inches 
above the top of the tuyeres, all around the cupola, and filled 
in the lining above with split brick and daubing, giving each 
cupola the shape indicated by the dotted lines. The cupolas 
were then charged as they were before the trouble began, and 
each one melted hot, even iron, throughout the heat and dumped 
clean. As soon as the man we had taught to melt saw us shape 
up a small section of the lining, he said : " Why, you told me to 
keep the linings in that shape and showed me how to do it two 
years ago." We said : "Why did you not do it?" He said he 
had forgotten it, and when the cupolas began to work badly, 
did not know what to do, and in fact had lost his head and let 
every melter under him do as they thought best. This is fre- 
quently the case with good melters. They forget points that 
they have learned in melting, have no literature upon the subject 
from which to refresh their memories, or melters to consult who 
are competent to advise, and gradually drift into a routine of 



EXAMPLES OF BAD MELTING. 

Fig. 53. 



241 




SECTIONAL VIEW OF LINING OUT OF SHAPE. NO. 4. 



16 



242 THE CUPOLA FURNACE. 

work, and when anything goes wrong with the melting do not 
know how to overcome the difficulty. 

BAD MELTING AT A WEST TROY STOVE WORKS. 

In 1882, we visited the foundry of Daniel E. Paris & Co., 
West Troy, N, Y., and while waiting for Mr. Paris, looked over 
the cupola. We found the lining in a condition indicating very 
poor melting and knew they were having some trouble with 
their iron. When Mr. Paris returned and learned who we were, 
he informed us that their foundry had recently burned down and 
they had moved into the present one, which had for some time 
before been idle. The boiler and engine were small and they 
were having some trouble in melting for want of power to drive 
a Sturtevant blower, which when run at a proper speed was 
large enough for the cupola. They were also endeavoring to 
melt up a lot of scrap from their recent fire, and had also pro- 
cured some of the best brands of No. i Pennsylvania irons and 
Scotch pig to melt with it, but were having some hard cast- 
ings. He wished to know if we could suggest anything to help 
them out until they could put in a new engine and boiler, and 
find some softer pig iron to work up the scraps, and he took us 
out to look over the works to see what change could be sug- 
gested. 

We looked over the blower and machinery, which were only 
those employed in stove mounting, and then went into the 
engine and boiler room, where we found a good-sized engine 
and boiler and decided that they were large enough to run the 
blower and all the machinery in the works at the same time. 
The engineer at once informed us that they were too small and 
he could not run any of the mounting machinery when the blast 
was on, or pump water into the boiler, without reducing the 
speed of the blower, and he had to fill the boiler and stop the 
engine for half an hour before putting on the blast to get up 
steam. We then went into the foundry, where we found a well 
arranged eupola of fifty-four inches diameter inside the lining, 
and learned that they were melting about eight tons of iron 



EXAMPLES OF BAD MELTING. 243 

each heat; that from four to four and a half hours were re- 
quired to run ofif the heat, and they were melting seven pounds 
of iron to the pound of anthracite coal. The iron melted so 
slowly that it was difficult to catch four hand-ladles full to 
pour off d, four up before the first ladle-full was too dull to run 
the work, and the iron was sometimes so hard that the plate 
cracked when taken out of the sand or when knocking off the 
gates. 

We then went upon the scaffold, where we found the coal 
when charged was not weighed, but measured in a basket and 
dumped from the basket into the cupola. We afterwards 
weighed a basket of coal filled as the melter generally filled it, 
and found it weighed almost twice as much as the melter stated, 
and with the extra weight of coal in the basket and the extra 
shovelfuls the melter said he threw in to fill up holes, we con- 
cluded that they were melting about three pounds of iron with 
one of coal, in place of seven to one as claimed by the melter. 
No slate was used in charging, sprews and gates were not 
weighed, but the weight estimated by counting the shovelfuls, 
and pig was weighed by counting the pieces, estimating four 
pieces to the hundred weight. The greater part of the coal, 
when dumped into the cupola from the basket, fell directly 
under the charging door, where it remained ; and the greater 
part of the iron naturally went to the opposite side of the 
cupola, and this uneven charging naturally produced uneven 
melting. 

We pointed out to Mr. Paris that his cupola lining was not 
glazed in front of the charging door, but was rough and jagged, 
as linings generally are in cupola stacks, which is an indica- 
tion that too great a quantity of fuel is being consumed in 
melting and that by using less coal better melting would be 
done. He thought seven to one was very good melting and 
knew none of the foundries in Troy were doing any better, and 
did not think iron could be melted sufficiently hot for their work 
with a greater ratio of iron to fuel than was being consumed in 
their cupola. But he was getting very poor results in melting, 



244 THE CUPOLA FURNACE. 

and after considerable talk he concluded to let us try a heat the 
following day with less fuel. 

The following morning when we went round to have the cu- 
pola prepared for a heat, we found the matter of less fuel had 
been talked over by the entire foundry force and by them con- 
demned. They argued that dull iron had been melted with the 
quantity of fuel used, and could not be poured at all if less fuel 
were used. It is a curious fact that moulders working piece 
work and losing work every day from dull iron will object to a 
stranger, or any man whatever but the melter making any 
change in the management of the cupola, or as they term it ex- 
perimenting with the cupola. While getting the cupola ready 
for a heat, the moulders came to us at the cupola or in the 
yard, one after another, and asked us all kinds of questions 
about melting, and Mr. Paris came also and asked us if we 
were sure we could melt iron hot enough for their work with 
less fuel than they were using, also if we had ever done so 
before ; and we found that we would have to be very careful 
what we said or did, or we would not be permitted to run off 
a heat. 

The melter was an old hand, who had melted iron in a num- 
ber of the foundries in Troy and was considered good. He 
was very much opposed to having us do any better melting in 
the cupola than he had done without a new engine and boiler, 
which he declared must be put in before anything better 
could be done. He knew all about it, and to teach this man to 
melt with less fuel would only be a waste of time, for he would 
probably in less than a week drift back into the same old rut 
if not closely watched, and would condemn our way of manag- 
ing a cupola. So we told Mr. Paris we could teach his fore- 
man to melt in a few days so that he could oversee the work 
and teach a man to do it in case his melter was sick or quit, 
and that it would be much better for them than for us to show 
their melter how to work with less fuel. After consulting the 
foreman it was decided that we should teach the foreman, and 
he went on the scafifold with us. He had the cupola made 



EXAMPLES OF BAD MELTING. 245 

up as we directed, sent to a store and purchased a new slate 
and arranged a system of mixing and charging the iron so 
that it would produce an even grade when melted, having 
had the scales dug out of a pile of rubbish in a corner and 
cleaned up, and the iron and fuel placed conveniently for 
charging. 

After everything had been arranged for the heat we had a 
little time to spare, and made it a point to see some of the lead- 
ing moulders and explained to them that we had shaped the 
lining so that the cupola would melt faster and with a little less 
fuel than they had been using, and make hot iron. We also 
saw the engineer and informed him that we would charge the 
cupola in a way that it would demand less blast, and if he filled 
his boiler and had a good. head of steam on just before putting 
on the blast, he could run all the machinery required for mount- 
ing when the blast was on. These explanations seemed to 
satisfy everybody, and the foreman was so enthusiastic in learn- 
ing to melt that we had no further fear of being run out of the 
works, and were looked upon as the man who understood his 
business until the heat was all charged into the cupola, when 
the melter went into the foundry and said to the moulders : 
" Be jabers yees will not pour off to-day boys, for that cupola 
will not make hot enough iron for yees with all the coal I was 
after putting in, and that man has left out half of the coal I put 
up for the heat. Yees may as well go home and save your 
moulds for to-morrow's heat; for yees will not run your work 
to-day." 

From that time until the blast went on, we were looked at 
shyly by all the moulders except two, who had seen us melt in 
other foundries ; but the foreman and these two assured them 
that we understood our business and they would have a good 
heat, which probably saved us from being driven out, for there 
was a tough lot of stove- moulders in Troy in those days, who 
considered their rights sacred and that no punishment was too 
great for any man who encroached upon them. 

When the blast was put on, the moulders gathered round the 



246 THE CUPOLA FURNACE. 

cupola and watched every tap until the iron came down so hot 
and fast that the first turn could not handle it, and the second 
turn was called up, and they were all kept on the run until the 
end of the heat. Getting iron so fast and hot was something 
the moulders had never been used to in that foundry, and a 
number of them wished to know if we were trying to kill them 
all by giving them the iron so fast. But all were delighted 
with getting hot iron to pour ofT their work and getting through 
so early ; and as we went along the gangways to see how the 
castings were turning out, a number of them asked us to wait 
until they were shaken out and have a glass of ale with them, 
which was the great drink of the Troy moulders. Had we 
waited for them we probably would not have reached our hotel 
that evening, for almost all of thepi dropped into a nearby 
saloon after they were through with their day's work, and we 
should have been asked to drink with every one of them. 

In this heat we had used considerably more coal than we 
considered necessary, as we were not familiar with the working 
of the cupola and desired to be on the safe side and make hot 
iron, even though the melting was a little slow, which was the 
case. Two hours were required for the heat, but even this 
length of time was fully two hours better than they had been 
doing, and all the machinery required for mounting was run 
during the heat without stopping the engine for half an hour to 
get up steam before putting on the blast. 

On the following day we reduced the coal a little more, and 
on the third day reduced it until we were melting six and a half 
pounds of iron to one of coal, and the heat was melted in one 
hour and thirty minutes. This was as fast as the moulders 
could handle the iron ; and as we did not consider it safe to 
melt iron for stove plate with less fuel, although we could have 
done so, and they did not desire it melted any faster, we made 
no further attempt to save fuel or reduce time of melting. 

The foreman learned very rapidly, and at the end of three 
days was fully competent to oversee the work, and they had no 
further trouble in melting or with hard iron, and were able to 



EXAMPLES OF BAD MELTING. 247 

melt up all the scrap from their recent fire with the brands of 
pig iron they had on hand, and it was not found necessary to 
put in a larger engine and boiler to get a sufificient blast, after 
they had learned how to manage the cupola. 

The cause of bad melting in this foundry was plainly indi- 
cated to an experienced melter at first glance by the lining 
in front of and around tl\e charging door, namely, too great 
a quantity of fuel in the cupola and too small a volume of blast 
for that fuel. So large a quantity of fuel was charged for a bed 
that the iron placed upon it did not come within the melting 
zone, and could not be melted until the surplus fuel burned 
away and permitted it to settle into the zone. Each charge of 
fuel to replenish the bed was too heavy, and the greater part of 
it had to be consumed before the iron placed upon it was per- 
mitted to enter the melting zone, and the slow melting was due 
to the time required in consuming the surplus fuel before the 
melting could take place. The hard iron in parts of the heat 
was due to uneven charging, which permitted the scrap at times 
to be melted by itself and drawn from the cupola without being 
mixed with melted pig, and the entire mass of iron was 
hardened by being subjected for a long time to a high degree 
of heat before it was permitted to enter the melting zone and be 
melted. 

The speed of the blower had been increased to fully double 
the number of revolutions per minute given in the directions for 
running it, to increase the volume of blast ; but the volume of 
blast had been decreased in place of being increased, as was 
supposed it had been by the increase of speed, and the cupola 
received less blast. 

We had no means of definitely determining to what extent it 
was decreased, but from the appearance of the blast in the 
cupola at difTerent stages of the heat, before and after decreas- 
ing the speed of the blower, we concluded that the volume of 
blast was increased fully one-half, by running the engine at its 
normal speed and reducing the speed of the blower to the 
number of revolutions given in the directions for running it. 



248 THE CUPOLA FURNACE. 

This is one of the cases where the cupola air-gauge in 
common use would have been of value, for it would have indi- 
cated a high pressure of blast before the speed of the engine 
was increased, and located the trouble at the cupola in place of 
at the engine. 

WARMING UP A CUPOLA. 

In 1 88 1 we visited the plant of the Providence Locomotive 
Works, Providence, R, I. The superintendent, Mr. Durgon, we 
believe was his name, wished to know if we were the Kirk that 
wrote "The Founding of Metals." We informed him that we 
were, and he replied that we might know all about a cupola, but 
our directions there given for constructing a cupola were no 
good, for he had constructed a cupola on that plan and it was a 
complete failure. It would not make hot iron, or melt half the 
amount per hour stated, or melt the heat before bridging over 
and bunging up. We informed him that if he had constructed 
the cupola exactly on the plan given it would do the work 
stated it would do. He invited us to go into the foundry and 
look the cupola over, and if it was not right he would make it 
right. We accepted the invitation and looked the cupola, 
blower and pipes all over, and could find no fault with them. 
The cupola was in blast at the time and we watched it melt 
for an hour, and it certainly was a complete failure. The iron 
from the beginning to the end of the heat was dull, the melt- 
ing slow, and the castings dirty and much harder than they 
should have been with the quality of iron melted. 

We knew that the trouble lay in the management of the 
cupola, and decided to go round the next day and see the 
melter make it up for a heat. This the superintendent de- 
cided to let us do, although he thought he had the best melter 
in New England and the trouble could not be in the manage- 
ment of the cupola. On the following day we were on hand 
early and found the cupola badly bridged and bunged up. 
The melter soon had it chipped out and daubed up in good 
shape, and we saw that the trouble was not in the shape of the 
lining. He then put in a very nice sand bottom from which 



EXAMPLES OF BAD MELTING. 249 

there could be no trouble in melting. He next put in shav- 
ings and a large quantity of wood, which he burned to dry the 
daubing. After this had been dried he added more wood and 
a good bed of hard coal which he burned up to warm the 
cupola for melting, and he certainly did give it a good warming, 
for when the doors were opened for charging the lining was 
heated to a white heat from the bottom to the stack. He then 
added a little more coal to level up the bed, and began 
charging. 

As soon as we saw the extent to which the lining had been 
heated and the bed burned, we knew that the cause of the poor 
melting lay in the bed. In warming the cupola up for melting, 
the life had all been burned out of the coal and but little of it 
left to melt with. The cupola was filled with ashes below the 
tuyeres, and even if iron was melted hot it would be chilled in 
its descent through these ashes to the bottom of the cupola. 
The fuel thrown in just before charging was flaked off, broken 
and burned up by the intense heat almost before the iron could 
be charged, and had it not been that an extra high bed was put 
in before warming up, not a pound of iron would have been 
melted. 

We had frequently seen beds burned too much, but had never 
seen one*burned to the extent of this one, or a cupola heated so 
hot before charging, and we stayed on the scaffold during the 
filling of the cupola with stock to see if the intense heat in the 
cupola had any effect upon the stock that would improve the 
melting in any way. The first charge seemed to be heated to 
a considerable extent by the hot lining and bed, and prepared 
for melting. After this charge was put in, the cupola cooled ofif 
very rapidly, and before it was filled there was scarcely any per- 
ceptible heat at the charging door, and the stock could not 
have been heated to any extent above the first or second 
charge, by warming of the cupola. When the cupola had been 
filled the blast was put on, and the iron melted exactly as we 
had seen it do the day before, dull and slow. The cupola had 
been properly made up ; plenty of fuel had been put in to make 



250 THE CUPOLA FURNACE. 

hot iron , charges of fuel and iron were of about the right pro- 
portion, and had been properly placed in charging, and there 
could be no doubt that the trouble in melting lay in the bed, as 
before stated. 

The following day the superintendant put the melter on the 
other cupola and gave us full charge of the one constructed on 
our plan. We had it made up in about the same way as the 
melter did ; put in our shavings, wood and all the bed, but a 
few shovelfuls to level up with before lighting up. After light- 
ing up we waited until the heavy smoke was burned off and 
the fire began to show through the top of the bed. We then 
leveled up the bed and began charging. The only change we 
made in charging was to reduce the fuel in the bed about one 
fourth, and that in the charges a little. When the blast was 
put on iron came down in about ten minutes, melted fast and 
hot throughout the heat, and the same amount of iron was 
melted in one half the time it had been the previous day. 
This convinced the superintendant that the cupola was all 
right, for it did all we claimed it would do and a little more, 
and it convinced us that there was nothing to be gained in 
melting by warming up a cupola before charging. 

BAD MELTING, CAUSED BY WOOD AND COAL. 

In one of the leading novelty foundries in Philadelphia that we 
visited some years ago they were employing two cupolas, one 40 
inches and the other 30 inches inside diameter, to melt 8 tons 
of iron, and it was very difficult to melt that amount in these 
cupolas. We knew that something was wrong and went upon 
the scaffold to look into the cupolas and found the melter just 
putting in the wood for lighting up. He had put in quite a 
lot of finely split wood, and had another barrow ready to add. 
After this was in, he went down and got three more barrows 
of cord-wood sawed in two and added this and then some long 
wood, and when he had it all in, the cupola was filled to the 
bottom of the charging door. He then filled the cupola with 
coal to the top of the charging door, putting in the largest 



EXAMPLES OF BAD MELTING. 25 I 

lumps he could find. We asked him why he put in so large a 
quantity of wood, and he said it was necessary to light the coal; 
and we presume it was, for some of the pieces of coal were as 
large as he could lift and place in the cupola, and it would re- 
quire considerable heat to start a fire with such large coal ; and 
he said they could not melt with any smaller coal. We tried 
to convince him that the cupola would melt better with less 
wood and smaller coal, but this was impossible, for he was an 
old melter and knew all about it. 

Either one of these cupolas would have melted the amount 
of iron they were getting in the two, and in less time, had they 
been properly managed ; but this was not done and the firm 
afterwards put in two Colliau cupolas to do the work. The 
cause of poor melting in these cupolas was too great a quan- 
tity of hard wood, which took a long time to burn out and in 
burning out the bed was burned to so great an extent that the 
cupola was filled with wood ashes and coal ashes before melt- 
ing began. The large lumps of coal also contributed to the 
poor melting by making an open fire through which the blast 
escaped freely without producing a hot fire, such as would have 
been produced by smaller coal. 

POOR MELTING IN A CINCINNATI CUPOLA. 

In Fig. 54 is seen a sectional elevation showing the condition 
of a small cupola we saw in Cincinnati, Ohio, a few years ago. 
This cupola would not melt, the founder said, and could not be 
made to melt. He had put in a new fan, and now his melter 
wanted a blower, and said the cupola would not melt without a 
forced blast. We examined the cupola, and suggested to the 
founder that he needed a new melter worse than a new blower. 

The cupola had not for a long time been properly chipped 
out, and a belt of cinder and slag varying in thickness from four 
to six inches had been permitted to adhere to the lining around 
the cupola above the melting point, and another belt of cinder 
and slag projected from the lining. Between these two project- 
ing belts the lining had burned away, making a deep hollow at 



252 THE CUPOLA FURNACE. 

the melting point. Entirely too much fuel had been consumed 

Fig. 54. 



a 



ILLUSTRATION OF BAD MELTING. 



EXAMPLES OF BAD MELTING. 253 

in melting or the belt of cinder and slag could not have formed 
above the melting point. 

We had all the projecting humps chipped off and the hollows 
filled in with fire-brick and daubing, so as to give the lining an 
even taper. The cupola was then properly charged, and there 
was no trouble in melting iron hot and fast. 

UNEVEN BURNING OF THE BED. 

We were once compelled to dump a cupola at the foundry of 
Perry & Co., from the carelessness of the melter in placing the 
shavings and wood in the cupola in such a way that they did 
not light up the fuel evenly, and in putting on the blast when 
the bed was only burned up on one side. We had not noticed 
it, and he thought the blast would make it burn up on the other 
side. This it did not do, and after the cupola had been in blast 
a short time, it had to be dumped. 

The careless way in which shavings and wood are often 
thrown into a cupola from the charging door, frequently causes 
an uneven burning of the bed and bad melting. We had a 
number of poor heats in our own foundry, due to this kind of 
carelessness, before discovering the cause of them. 

We might relate many more examples of poor melting in 
various foundries, but these will probably suffice, as the causes 
of poor melting when a cupola is properly constructed will 
generally be found in the shape of the lining, burning of the 
bed, or quantity of fuel used in melting; examples of which are 
here given. 



CHAPTER XVI. 

MELTERS. 

There is no man about a foundry for whom we have more 
respect than a practical and scientific melter. He is generally 
a self-made man and has learned the art of melting himself. He 
is a man of intelligence, who, perhaps, has been a melter's 
helper and a close observer of the work, and when given charge 
of a cupola, has followed in his footsteps or improved on the 
methods of his predecessors. He may have been a man who 
was given a few instructions in melting when he first began, and 
has become an expert through his own efforts. He is respected 
by the foreman and moulders, and well-paid by his employer. 
There is no man about a foundry for whom we have more pity 
than a poor melter, for he seldom melts two heats alike, and is 
cursed by the piece moulders who have lost their work through 
bad iron. Gibed b)^ the day moulders, lectured by the fore- 
man, looked black at by his emploper, poorly paid, and re- 
spected by no one about the foundry, his lot is a hard one. 

A poor melter is not always to blame for doing poor work, 
for he may have been a foundry laborer who was put to work 
as a melter, and never given proper instruction in the manage- 
ment of a cupola. Again, a good melter may be made a poor 
one from being interfered with by others who do not under- 
stand melting. Foundrymen in conversing with each other 
learn that they are melting ten pounds of iron to the pound of 
fuel. The foundryman not being a practical man, does not 
inquire the size of the heat or cupola in which it is melted, the 
conditions under which it is melted, or the kind of work the 
iron is for. He does not stop to think that the other foundry- 
man may be lying to him, or is deceived by his melter and 

(254) 



MELTERS. 255 

does not know how many pounds of iron he is melting to the 
pound of fuel. But he goes to his foundry and insists that iron 
must be melted at a ratio of 10 to i. The conditions in his 
foundry may be totally different from those of the other one, 
and iron may not be melted at a ratio of 10 to i in the other 
foundry. The melter, if he is a practical man, knows this, or 
finds it out the first heat, and to hold his job shovels in extra 
fuel, unbeknown to any one, and if he is watched, does not get 
it in evenly or at the proper time, and the result is uneven melt- 
ing and dull iron. Foundrymen do not always furnish their 
melters with proper tools for chipping out and making up the 
cupola, a suitable material for repairing and keeping up the 
lining, a proper flux for glazing the lining and making the cu- 
pola melt and chip out free, and a man who would be a good 
melter if given a chance, is frequently made a poor one by 
being hampered in his work for want of tools and material to 
work with. He is blamed for poor melting when it is really not 
his fault. Good melters frequently get into a rut or certain 
way of doing their work, for want of text-books and other liter- 
ature on melting to read and study, or association with men of 
their calling, and become very poor melters. As a lawyer who 
does not read law-books that are up to the times and associate 
with his colleagues, becomes a pettifogger, so does a doctor 
who does not study his text- books and medical literature, diag- 
noses all cases as one of two or three diseases, has one or two 
prescriptions which he prescribes for all cases. The man of 
learning, or a man who knows it all, when left to himself for 
years gets to know nothing ; and so it is with melters when left 
to themselves. They forget many things they are not called 
upon to practice every day, and in time get into a rut or routine 
from which they unconsciously gradually degenerate if the mind 
is not refreshed by reading or contact with other melters. It 
should be the aim of every melter to converse with other 
melters upon cupola matters at every opportunity, and to read 
and study all literature upon the subject, whether good or bad ; 
for, if good, he may learn something new, and, if bad, it stimu- 



256 THE CUPOLA FURNACE. 

lates the mind to reason why it is not good, and how it can be 
improved upon. It recalls to mind facts in his own experience 
which have long been forgotten, and he learns something, at all 
events. It is to the interest of every foundryman who depends 
upon his melter for results to keep him posted upon all that is 
new in the business, and he should furnish him all the new lit- 
erature on the subject that comes into his office or is published. 



CHAPTER XVII. 

EXPLOSION OF MOLTEN IRON. 

Molten iron is a very explosive body, and under certain 
conditions explodes with as loud a report and as much vio- 
lence as gunpowder. Under other conditions it is not at all 
explosive, but the conditions under which it explodes must be 
fully understood and avoided by melters and moulders to pre- 
vent dangerous accidents. 

A stream of iron fiows from a tap-hole and spout smoothly 
if the front and spout lining have been properly dried. When 
wet the iron explodes as it emerges from the tap hole and is 
thrown in small particles some distance from the cupola. The 
instant a stream of iron strikes a wet spout it explodes and the 
entire stream is thrown from the spout in all directions with 
great force. In a damp spout the iron boils and small particles 
may be thrown ofT, but the explosion is not so violent as from 
a wet spout. 

A wet bod causes molten iron to explode the instant it 
comes in contact with the stream, and it is impossible to close 
a tap hole with it. A bod containing a little too much mois- 
ture causes a less violent explosion and a tap hole may be 
closed with it, but in closing it, the iron explodes and is fre- 
quently thrown from the tap hole with great force past the 
sides of the bod before it is pressed into the hole. When the 
bod is in place in the hole one or more small explosions fre- 
quently take place, and the bod-stick must be firmly held 
against the bod to prevent it being blown out. The kick or 
thump felt against the end of a bod-stick when pressing a bod 
into place is due to these explosions, and not to the pressure 
of molten iron in the cupola, as is generally supposed. Bod 
17 (257) 



258 THE CUPOLA FURNACE. 

material should be no wetter than moulding sand properly tem- 
pered for moulding. 

When the iron is very hard, a stream of very hot iron throws 
off a great many sparks from a dry spout. These sparks are 
caused by an explosion of the iron due to the combination of 
oxygen with the combined carbon of the iron, and the sparks 
are the oxide of iron. They contain very little heat, and melters 
or moulders do not hesitate to enter showers of these sparks to 
stop in or catch the stream of iron. The sparks from explo- 
sions caused by dampness are of an entirely different character, 
and burn the flesh or clothing wherever they strike. 

A wet, cold or rusted tapping bar thrust into a stream of iron 
in the tap hole or spout, causes the iron to explode. Tap bars 
should, therefore, always be heated before they are put into the 
stream of iron. 

When iron falls from a spout upon a hard floor, it spatters 
and flies in small particles to a considerable distance from the 
place it first strikes, and it is dangerous to go near the spout as 
long as the stream is falling upon the floor. 

When iron falls from a spout upon a wet, muddy floor, it ex- 
plodes instantly, and small particles of molten iron may thus be 
thrown a hundred feet from the cupola. If the stream continues 
to run upon the floor, one explosion follows another in rapid 
succession, or a pool of molten iron is formed, which boils and 
explodes every few minutes, as long as there is any moisture in 
the floor and the iron remains liquid. The floor under a spout 
should always be made of loose dry sand, with a hole in it to 
catch any iron that falls from the spout. 

The floor under a cupola should always be dry, and when 
paved with brick or stone, should be covered with an inch or 
two of dry sand before dumping, to prevent fluid iron or slag 
in the bottom of the cupola spattering or exploding when 
dumped. 

Molten iron explodes violently when a piece of cold, wet or 
rusted iron is thrust suddenly into it, as the writer has reason 
to know from practical experience, when working at stove 



EXPLOSION OF MOLTEN IRON. 259 

moulding in the winter of 1 866 and 1 867. Knowing that a rusty 
or wet skimmer made iron explode, we always took the pre- 
caution of putting our skimmers into the foundry heating stove 
and heating them to a red heat before catching iron. One day 
we had taken the precaution, heating a skimmer to a red heat 
and putting it in a convenient place for use. A small boy who 
was around the foundry and sometimes skimmed our iron before 
pouring, saw the red-hot skimmer, and took it out and put it in 
the snow, while we were catching a ladle of iron, As soon as 
we set the ladle on the floor he ran in with the skimmer dripping 
wet, and before we could prevent him, thrust it into the molten 
iron. The iron exploded instantly and was thrown all over us 
as we leaned over the ladle, burning us so severely that we were 
not able to be out of the house for several weeks, and we still 
carry many scars from those burns. The iron was thrown with 
great violence, and passed through our clothing and a thick felt 
hat, like shot from a gun. The exploded iron passed over the 
boy's head and he was burned slightly, but never was seen 
about the foundry again, and probably never became an iron 
moulder. 

Molten iron when poured into a damp or rusted chill-mould 
or a wet sand-mould, explodes and is thrown from the mould, 
and escaping from a mould upon a wet floor or into the bot- 
tom of a wet pit, explodes. In the foundry of Wm. McGilvery 
& Company, Sharon, Pa., a deep pit for casting rolls on end 
was put in the foundry floor and lined with boiler plate. The 
first roll cast in this pit was one eleven feet long, weighing 
about five tons, moulded in a flask constructed in ring sections 
and clamped together. The mould was not properly made and 
clamped, and when almost filled with molten iron gave way 
near the bottom and permitted the iron to escape into the pit, 
the bottom of which was covered with wet sand or mud. The 
iron at once exploded and forced its way up through ten feet 
of sand that had been rammed about the mould in the pit, and 
was thrpwn up to the foundry roof at a height of forty feet. The 
molten iron continued to explode until fully four tons were 



26o THE CUPOLA FURNACE. 

thrown from the pit in small particles, and the foundry burned 
to the ground. 

Molten iron explodes when poured into mud or brought in 
contact with wet rusted scrap, but does not explode when 
poured into deep or clean water. At a small foundry that 
stood near the Pittsburg & Erie canal, in Sharon, Pa., many 
years ago a wager was made by two moulders that molten 
iron could not be poured into the water of the canal without 
exploding. A ladle of iron was accordingly taken to the 
canal and poured into the water without any explosion taking 
place. A few days later an apprentice boy who had witnessed 
this experiment undertook to pour some into water in an old 
salt kettle that sat in the yard near the foundry and contained 
rusted scrap and mud under the water. An explosion at once 
took place that almost wrecked the foundry. The water in this 
case was not of sufificient depth to destroy the explosive pro- 
perty of the molten metal before it came in contact with the 
rusted scrap and mud at the bottom of the kettle. 

Moulders frequently pour the little iron they have left over, 
after pouring ofT their day's work, into a bucket of water to 
heat the water for washing in cold weather. This was a com- 
mon practice of the moulders in the foundry of James Marsh, 
Lewisburg, Pa., until one day iron was poured into a bucket of 
water in which clay wash had been mixed and contained mud 
at the bottom. It exploded instantly with so great a violence 
that all the windows were blown out of the foundry, and this 
stopped the heating of water for washing, in that way, at that 
foundry. 

At another foundry, iron poured into clear water in a rusted 
cast-iron pot exploded, doing great damage. 

At the foundry of North Bros., Philadelphia, Pa., during the 
flood in the Schuylkill river June, 1895, the cupola was pre- 
pared for a heat and the blast put on ; but before the heat could 
be poured off water soaked into the cupola pit and had to be 
bailed out to prevent the pit being filled. The heat was all 
poured before water came upon the moulding floors, but the 



EXPLOSION OF MOLTEN IRON. 26 1 

bottom of the cupola pit was soaking wet, and the melter, in his 
eagerness to leave the foundry before it was flooded, dropped 
the bottom without drawing off the molten iron remaining in 
the cupola. The instant the molten iron and slag dumped from 
the cupola came in contact with the wet floor of the pit, a vio- 
lent explosion took place, scattering molten iron, slag and fuel 
in all directions and blowing all the windows out of the foundry. 
Had the melter taken the precaution to have drawn ofif all the 
molten iron before dumping, and thrown a few shovelfuls of dry 
sand under the cupola to receive the first slag to fall upon the 
bottom, this explosion would not have taken place. 

At the foundry of The Skinner Engine Co., Erie, Pa., a vio- 
lent explosion took place in their cupola which almost entirely 
wrecked it. At the time of this explosion, a lot of small 
steam cylinders were being melted in the cupola, and in some 
of these cylinders the ports of the steam-chest had been closed 
by rust, leaving the steam-chest filled with water, from which 
it could not escape. The foreman, David Smith, had given 
the melter orders to see that each of these cylinders was 
broken before being put into the cupola, but this order had by 
the melter been disregarded, and the explosion was attributed 
to the water confined in one of the cylinders being converted 
into steam and exploding with such violence as to wreck the 

cupola. 

At the foundry of The Buffalo School Furniture Co., Buffalo, 

N. Y., an explosion took place in 1895 in their sixty-inch cupola, 
about seven minutes after the blast was put on for a heat, which 
blew the heavy cast iron door from the tuyere box, on each 
side of the cupola ; and also blew out the front and broke the 
heavy cast-iron bottom doors. A number of men who chanced 
to be near the cupola were severely burned, but fortunately 
none were killed. This explosion was attributed to a number 
of causes, one which was the formation of gas in the cupola be- 
fore the blast was put on, which was exploded by the addition 
of oxygen from the blast. But this could hardly have been the 
cause, for the blast had been on fully seven minutes before the 



I 



262 THE CUPOLA FURNACE. 

explosion occurred, and had this been the cause the explosion 
would have taken place almost as soon as the blast was put on. 
Another cause given for the explosion was that dynamite had 
been placed in the cupola concealed in some pieces of scrap- 
iron. This may have been the case, or some other explosive 
body may have been concealed in the scrap; but it is just as 
probable that it was due to steam generated from water con- 
fined in some piece of the scrap, by rusting of the opening 
through which it was admitted to the casting; as in the case at 
the foundry of The Skinner Engine Co. 

A damp ladle causes iron to boil, and if the daubing is very 
thick may cause it to explode. A wet daubing or water in a 
ladle explodes the iron the instant it touches it. Wet or rusted 
scrap iron placed in a ladle to chill the molten iron, causes the 
iron if tapped upon it, or if thrown into a ladle of iron, to ex- 
plode. Such an explosion may be prevented by heating the 
scrap to a red heat just before using it to chill the iron. 



CHAPTER XVIII. 

SPARK CATCHING DEVICES FOR CUPOLAS. 

FoUNDRYMEN, whose plants are located in closely built up 
neighborhoods, are very much annoyed by sparks thrown out 
of their cupolas lighting upon the roofs of adjoining buildings 
and setting them on fire. In some cases they have on this 
account been compelled to move their plants from towns and 
cities to the suburbs. Many plans have been devised and tried 
for arresting these sparks ; one of the oldest and most efificient 
of which is the design shown in Fig. 55. This arrangement was 
devised when the old-fashioned cupolas with brick stack were 
in vogue, and was generally put up in such cases where cupola 
sparks were very objectionable. It consisted in constructing the 
stack upon an iron plate supported by iron columns, on a level 
with the top of the cupola. The end of this plate extended over 
the top of the cupola, with an opening in the plate equal to the 
inside diameter of the cupola, and on the plate was put a short 
stack, in which was placed the charging door, the top of which 
was arched over toward the main stack, with which it connected 
on the side. 

Any sparks that arose from the cupola were thrown into the 
bottom of the main stack by the arch in the direction indicated 
by the arrows and were removed when cold, as often as the 
bottom of the stack filled up to such an extent as to interfere 
with the arrest of the sparks. 

This arrangement was very effective in arresting sparks, but 
was not found to be a very convenient one for attaching to our 
modern cupolas, and numerous other plans have since been 
devised and used. 

(263) 



264 



THE CUPOLA FURNACE. 
Fir.. 55. 




SPARK CATCHER IN OLD STYLE CUPOLA. 



SPARK CATCHING DEVICE FOR MODERN CUPOLAS. 

In Fig 56 is seen a more modern spark-arrester than the one 
just described. In this device, the casing is cut in two at the 



SPARK CATCHING DEVICES FOR CUPOLAS. 265 

Fig. 56. 




u ^ 










r- ^ 

— I 


r- 




-^-y 

r^ 


r^=;J.... . 



SPARK CATCHING DEVICE IN MODERN CUPOLA. 



266 THE CUPOLA FURNACE. 

bottom of the charging door and an iron plate or ring placed 
upon the top of the cupola casing, where it is supported by 
the casing and cast-iron brackets riveted or bolted to it on the 
outside. The inside of the plate or ring generally cov^ers the 
top of the cupola lining to protect it when charging the stock, 
and the outside extends over the cupola casing from six to 
twelve inches. On this plate the stack casing, which is of 
larger diameter than the cupola casing, is placed and lined 
with a thin lining. The spark-arresting device consists in 
making the stack larger than the cupola so that the blast loses 
its force when it emerges from the cupola, and enters the stack, 
and the sparks carried out of the cupola fall back into it before 
reaching the top of the stack. The extent to which the stack 
should be enlarged to be efifective in arresting sparks depends 
upon the height of it; low stacks requiring to be of a larger 
diameter than high ones. 

In this illustration is shown a very neat arrangement for sup- 
plying blast to a cupola when a belt air chamber riveted to the 
cupola shell is not used. The main blast pipe AA which 
encircles the cupola is placed up out of the way, in catching 
iron or removing large ladles. The branch pipes are cast in 
one piece and tightly bolted or riveted to the main pipe and 
cupola casing, to prevent the escape of blast. The peep holes 
BB are cast in the pipe, and close with a tight-fitting swing cap 
and latch. 

RETURN FLUE CAPULA SPARK CATCHER. 

In Fig. 57 is shown a device designed by John O'Keefe, 
Superintendent of Perry & Go's Stove Works, Albany, N. Y., 
for catching sparks and saving fuel. The foundry of the firm 
in which this device was constructed, was located on Hudson 
St., in a closely built up part of the city, and they were very 
much annoyed by sparks from their cupola setting fire to roofs 
of buildings in the vicinity, and it became necessary to prevent 
sparks escaping or move their foundry. A number of devices, 
such as hoods, etc., were tried, but none of these proved effect- 
ive, and a return flue was constructed. The arch or dome A was 



SPARK CATCHING DEVICES FOR CUPOLAS. 26/ 

Fig- 57- 




RETI'RN FLUE CAPULA SPARK CATCHER. 



268 THE CUPOLA FURNACE. 

thrown across the cupola stack above the door, and the flue B led 
out of the cupola just below the dome and down to the foundry- 
floor, from which point it returned to the stack above the dome. 
When the cupola was in blast, waste heat from the cupola 
struck the dome and was thrown back upon the stock in the 
cupola, or was forced down through the flue B and returned to 
the cupola stack through the flue C above the dome. When 
the cupola was put in blast it was found that so large an amount 
of heat and gas escaped from the door that the cupola could 
not be charged when in blast, and it became necessary to make 
a small opening through the dome to permit part of it to es- 
cape. Had the cupola been of a size to admit of all the stock 
being charged before the blast was put on and the door closed, 
during the heat, there is no doubt considerable fuel might have 
been saved, and faster melting done. But as it was, no fuel 
was saved, and there was no perceptible change in the time re- 
quired to melt a heat. The device was eff"ective in preventing 
the escape of sparks and small pieces of fuel from the stack, for 
they were all thrown back into the cupola or deposited in the 
bottom of the flue, from which they were removed through the 
opening D at the bottom of the flue, as frequently as found 
necessary. 

OTHER SPARK CATCHING DEVICES. 

Another device for arresting sparks is to place a half circle 
fire-brick arch opened at both ends on the top of the stack, 
making its total length and breadth equal to the outside 
diameter of the stack. This plan arrests the sparks in their 
upward course and some of them fall back into the cupola, 
but many are carried out at the ends of the arch by the blast 
and fall upon the foundry roof, and on windy days may be 
carried to adjoining roofs. 

Iron caps or hoods are also placed one or more feet above 
the top of cupola stacks to arrest sparks ; but they, like the 
arch, only arrest the sparks in their upward flight and throw 
many of them down upon the foundry or scaffold roof. 

Anuther plan for preventing the escape of sparks is to sus- 



\ 



SPARK CATCHING DEVICES FOR CUPOLAS. 269 

pend an iron disk of a few inches smaller diameter than the 
stack in the stack near the top. The sparks strike this disk 
and are thrown back into the cupola. But this device cannot 
be used in contracted stacks with a strong blast, and in large 
ones the cohesive properties of the iron are soon destroyed by 
the heat and gases of the cupola, and if not frequently replaced 
there is danger of it breaking from the jar in chipping out the 
cupola, and falling upon the melter. 

THE KEST SPARK CArCHING DEVICE. 

The cause of sparks being thrown from a cupola is the 
strong blast forced into the cupola at the tuyeres, which 
carries small pieces of fuel out at the top of the stack during 
the heat, and large pieces near the end of a heat, when the 
stock is low in the cupola and the blast passes through it more 
freely. The lifting power of the blast is increased by confining 
it in a contracted stack, and good-sized pieces of fuel may be 
thrown several feet above the top of a small stack ; but the in- 
stant the blast escapes from the top of the stack it expands 
and its lifting power is lost, and sparks or pieces of fuel fall by 
their own weight and may in their descent be carried to some 
distance by a strong wind. 

To prevent them being carried out of the stack, it is only 
necessary to provide sufficient room in the stack for the blast 
to expand, after escaping from the cupola, and lose its lifting 
force, when the sparks will fall back in the cupola and be con- 
sumed. This may be done by constructing the stack casing of 
the same diameter as the cupola casing, and lining it with a 
thin lining of four-inch iire-brick supported by angle iron, so 
that the cupola lining rnay be removed or repaired without dis- 
turbing the stack lining. Cupolas constructed in this way, 
when the stack is of proper height, do not throw out sparks. 
When it is not desirable to have a very high stack, the enlarged 
stack shown in Fig. 56 may be used. The first cost of a stack 
of this kind is a little greater than that of a contracted one, 
but when properly constructed and lined, will last the life of a 



2/0 THE CUPOLA FURNACE. 

cupola. In fact we never knew one, if properly lined when 
constructed, requiring to be relined or repaired, and the saving 
effect by preventing damage to roofs, lumber, flasks, etc., 
from sparks will soon pay for the extra cost of construction. 
The objection usually made by foundrymen to large stacks is 
that they do not give sufificient draught for lighting up. This 
may be the case when the top of the stack is only a few feet 
above the charging door, but when given a proper height for 
arresting sparks there is always sufificient draught for lighting 
up. There are many cupolas constructed upon this plan in 
use at the present time, and they give better satisfaction than 
those with contracted stack. 



CHAPTER XIX. 

HOT BLAST CUPOLAS. 

A NUMBER of plans have in this country been at different 
periods devised for utilizing the heat escaping from the top of a 
cupola when in blast, for heating the blast before entering the 
cupola at the tuyeres. The best arranged cupolas of this kind 
that we have seen are those shown in Fig. 58. This pair of 
cupolas was made at Albany, N. Y., by the firm of Jagger, 
Treadwell & Perry. With a view of saving fuel and improving 
the quality of iron for light work, the two cupolas DD of thirty 
and forty- five inches diameter, respectively, inside the lining, 
and eight feet high were constructed, and were made of boiler 
plate ; the bottom and top plates between which the cupolas 
were placed were supported by four iron columns, and on the 
top plate were fitted the brick arches BB, which connected the 
cupolas with the brick ovens EE. In the rear of each cupola, 
between the ovens, was placed the high stack A. Each oven 
was filled with cast-iron pipe CC, through which the blast 
passed before entering the cupolas. When in blast, the escaping 
heat from the cupolas passed downward through the ovens as 
indicated by the arrows, and entered the stack A from the 
bottom of the ovens. The pipes were by the escaping heat 
carried up to a red heat, and the blast in passing through these 
coils of pipe was heated to a sufficient degree before entering 
the cupolas to melt lead. This plan was a success so far as 
heating the blast was concerned, but the blast could not be 
carried up to the above degree until the cupolas had been in 
blast for some time. Hence very little fuel was saved, for no 
economy in fuel could be effected until the blast was heated, 
and the cupolas had to be fully charged with fuel for the first 

(271 ) 



272 



THE CUPOLA FURNACE. 
Fig. 58. 




HOT BLAST CUPOLAS. 



HOT BLAST CUPOLAS. 273 

half of the heat. No perceptible improvement was made in the 
quality of the iron by the heating of the blast, and the greatest 
objection to these cupolas was the difficulty of keeping the coils 
of pipe intact. The heating of the pipe to a red heat every 
time the cupolas were put in blast and permitting them to cool 
before the next heat, in a short time destroyed the cohesive 
properties of the iron, and the pipe frequently broke after or 
during a heat and permitted the blast to escape into the oven. 
These breaks became so frequent and annoying after the pipe 
had been in use for a short time, and were so expensive to re- 
pair, that the slight saving effected in fuel did not justify a con- 
tinued use of the hot blast, and it was abandoned. The cupolas 
were for a long time used without the hot blast, and the ovens 
proved excellent spark catchers. No sparks were ever thrown 
from the top of the high stack, and the ovens had frequently to 
be cleaned to remove them. 

At the stove foundry of Ransom & Co., Albany, N. Y., a 
cupola was constructed with a large stack, and coils of pipe for 
heating the blast were placed in the stack directly over the 
cupola. The blast when passed through these pipes was heated 
to a high degree after the cupola had been in blast for a short 
time, but the pipes in this case broke after repeated heating and 
cooling, as in the ovens of the Jagger, Treadwell and Perry 
cupolas, and after the killing of a melter, by a piece of pipe 
falling upon him from the stack while picking out the cupola, 
the pipes were all removed from the stack and heating of the 
blast was discontinued. Several attempts have been made to 
take the escaping heat direct from the top of a cupola and re- 
turn it into the cupola through the tuyeres ; but in all cases 
this plan has, for lack of means to force the hot air into the 
cupola, proven a failure. 

Exhaust pipes have been connected with the stack of a cupola 
and the inlets of the blower placed near the cupola, and hot air 
drawn from the stack by the blower and returned to the cupola 
through the tuyeres. This arrangement supplied a hot blast to 
the cupola with no expense for heating the blast, and was in the 
18 



274 THE CUPOLA FURNACE. 

early part of a heat in which it was tried, a success, when only 
a small amount of heat escaped from the cupola and the air 
drawn from the stack was heated only to a limited extent. 
But, as the melting progressed and the stock settled low in the 
cupola, the air drawn from the stack was heaten to so high a 
a degree as to heat and destroy a blower through which it was 
passed in being returned to the cupola. Could hot air have 
been taken from a cupola stack and returned to the cupola 
through the tuyeres without passing it through a blower, it 
would, no doubt, have effected a great saving in fuel in the days 
of low cupolas, when a large amount of the heat from fuel direct 
was not utilized in melting. But this could not be done, and 
after a number of experiments to secure a hot blast in this way. 
the plan was given up as a failure. 

The blast for a cupola can be heated in a hot-blast oven simi- 
lar to those some years ago used in heating the blast for fur- 
naces, and which was done by furnaces specially constructed 
for the purpose, and not with gas taken from the furnaces as at 
the present time. But these ovens would be required to be 
kept continually hot to prevent breakage of the pipes by re- 
peated heating and cooling. The saving of fuel efifected in 
melting with a hot blast obtained in this manner, would not be 
sufificient to pay for the expense of heating the blast for a cupola 
that is only in blast for a few hours each day ; and it is doubtful 
if the saving efifected would justify the heating of the blast, if a 
cupola was kept constantly in blast, or the hot blast changed 
from one cupola to another as soon as the heat was melted. 

WASTE HEAT FROM A CUPOLA. 

A number of plans for utilizing the heat escaping from a 
cupola, besides using it for heating the blast, have been devised ; 
such as utilizing it for heating the iron before charging it into 
the cupola, drying cores, ladles, etc. All these experiments 
were made years ago, when from six to ten feet was considered 
to be the proper height for a cupola, and fully one-half of the 
heat escaped from the top ; but it was not until the height of 



HOT BLAST CUPOLAS. 275 

cupolas was increased that a practical means of utilizing all the 
heat of the fuel in melting was found. In a high cupola all the 
heat escaping from the melting zone is utilized to heat the stock 
in the cupola and prepare it for melting before the stock settles 
into the melting zone. The height that a cupola should be 
made in order to utilize all the heat depends upon its diameter, 
volume of blast, and the way in which the stock is charged. 
Cupolas of twelve to twenty inches in diameter must be made 
low, so that the stock in case it hangs up in the cupola may be 
dislodged with the bar, and all the heat cannot be utilized in 
these small cupolas except when a very small volume of blast is 
used. In this latter case the melting is slow, and it is more 
economical to permit part of the heat to escape, and do fast 
melting with a strong blast. Cupolas of large diameter may be 
made of a sufficient height to utilize all the heat, no matter how 
great the volume of blast or how openly the stock is charged. 
Cupolas of large diameter now in use in many foundries are 
from fifteen to twenty feet high, and those in the Carnegie Steel 
Works, Homestead, Pa., are thirty feet high. In these cupolas 
whole bars of pig iron are charged, and all the stock is dumped 
into the cupola from barrows, and no pains taken to pack it 
close to prevent the escape of heat. Yet no heat escapes from 
the top of the cupola when filled with stock, and it has not 
been found necessary to line the iron stacks with brick to pre- 
vent them being heated by heat escaping from the cupolas. 

In low cupolas heat may to a large extent be pre\'ented from 
escaping by breaking the pig and scrap into small pieces, and 
when charging packing it close. More time is then required 
for the heat to work its way through the stock in escaping 
from the melting zone, and a greater amount of it is utilized in 
heating the stock and preparing it for melting before it settles 
into the melting zone. 



CHAPTER XX. 

TAKING OFF THE BLAST DURING A HEAT — BANKING A CUPOLA — 
BLAST PIPES, BLAST GATES. 

EXPLOSIONS IN BLAST PIPES, BLAST GAUGES, BLAST IN MELIING. 

The length of time the blast can be taken off a cupola after 
it has been in blast long enough to melt iron, and put on again 
and good melting done, depends upon the condition of the 
stock in the cupola at the time it has been stopped. 

The blast may be taken off a cupola that has only been in 
blast for a short time, is in good melting condition and filled 
with stock, for many hours if the melted iron and slag are all 
drawn off and the tuyeres carefully closed to exclude the air 
and prevent melting and chilling after the blast has been 
stopped. We have known a cupola in this condition in case 
of a break-down in the blowing machinery to be held from four 
o'clock in the afternoon until eight o'clock the following morn- 
ing, and good melting done when the blast was again put on. 

In this case, the tuyeres were packed with new molding sand 
rammed in solid to completely exclude the air, and the molten 
iron all drawn off, after the tuyeres had been closed for a short 
time and the tap hole closed with a bod. Before putting on 
the blast in the morning, the tuyeres were permitted to remain 
open for a short time, to allow any gas that may have collected 
in the cupola during the stoppage to escape and avoid an ex- 
plosion, which might have occurred had a large volume of blast 
been forced into the cupola when filled with gas. 

Cupolas that have been in blast for some time and from 
which the blast is removed toward the end of the heat when 
the cupola is comparatively empty, or in bad shape for melt- 
ing, cannot be held for any great length of time, even if the 

(276) 



TAKING OFF THE BLAST DURINCx A HEAT. 277 

tuyeres are at once closed and every precaution taken to pre- 
vent chilling and clogging. This is due to the gradual settling 
of a semi-fluid slag and cinder above the tuyeres, and the clos- 
ing up of small openings in it through which the blast was dis- 
tributed to the stock ; and in case of accident to the blower it is 
better to dump the cupola at once than to attempt to hold it 
for any length of time. 

Cupolas, in which all the iron charged has been melted and 
drawn off, may be held over night, if the cupola has been 
properly fluxed, the slag drawn off, and a fresh charge of coke 
put in, with a liberal charge of limestone on top of it to 
liquefy any slag that may over night have chilled in the cupola. 
Small cupolas are frequently managed in this way ; the tuyeres 
are closed and the tap hole permitted to remain open to admit 
sufficient air to ignite the fresh coke. 

In the morning after the cupola has been filled with stock 
and the blast put on, the limestone on the bed is the first to 
melt, and if in sufficient quantity makes a fluid slag that 
settles to the bottom, freeing the cupola of any clogging that 
may have taken place during the stoppage. 

BANKING A CUPOLA. 

Since writing the foregoing paper we have received the fol- 
lowing practical illustration of keeping a cupola in good con- 
dition for melting for many hours after it had been charged 
and the blast put on, from Mr. Knceppel, Foundry Superin- 
tendent, Buffalo Forge Co., Buffalo, N. Y. In this case melt- 
ing had not begun before the pulley broke and the blast was 
taken off, but the same results would have been obtained from 
banking the cupola in this way if melting had begun and the 
cupola been in blast for a short time. 

" Banking a cupola is something that does not come in the 
usual course of foundry practice, but there are times when the 
knowledge of how it is to be done would be a source of profit, 
as well as loss of time being averted. By request having been 
induced to allow this letter to appear in your valuable publica- 



278 TliE CUPOLA FURNACE. 

tion on 'Cupola Practice;' hence willjtryrand give you the 
details as near as I can from memory, although I wrote an arti- 
cle on this subject in the 'American Machinist,' December 10, 
1 89 1, which I am now unable to get. 

"In the latter part of October, 1891, just as we were about to 
put on the blast in our foundry cupola and the fan making a 
few revolutions, the main pulley broke, running the main shaft 
to the fan or blower of our cupola. After considerable trouble, 
loss of time and delay in trymg to get a new pulley, which was 
of wood pattern, we finally succeeded in getting one of the 
proper size, and had it put on the shaft; but the belt being a 
little tight, and also anxious to get ofT the heat, in slipping the 
belt on the pulley, it was cut in such a shape that it became use- 
less for that day. By this time it was beyond our regular hour 
for quitting. At first there seemed no way out of the dilemma 
but to drop the bottom. The thought of re-handling the hot 
material and fuel, the extra labor attached therewith, suggested 
the idea of holding up the charges until next morning, when 
repairs would be completed. After a few moments' consulta- 
tion, proceeded as follows : Let me say first that the cupolas 
was lighted at i : 45 p. m. and at 6 p. m. began the operation 
of banking the cupola, having had four hours and fifteen min- 
utes' time for burning the stock, and being charged with eleven 
tons of metal. The cupola was of the Colliau type 60" shell 
lined to 44" at bottom and 48'' at melting zone, having six 
lower tuyeres, 7'' X 9", upper tuyeres being closed. Height of 
tuyeres from bottom when made up 18'', blast pressure 10 oz., 
revolutions of blower about 21 00, manufactured by the Buffalo 
Forge Co., and known as No. 10, the adjustable bed type. The 
cupola bed was made up of 600 lbs. Lehigh lump coal and 800 
lbs. Connellsville coke, the succeeding charges 50 lbs. of coal 
and 150 lbs. coke, coal being an important factor in this heat 
on account of its lasting qualities. We first cleaned and cleared 
all of the tuyeres, packed each one with new coke, and then filled 
and rammed them tight with floor moulding sand to prevent 
any draft getting through them, and had the top of charges 



{ 



TAKING OFF THE BLAST DURING A HEAT. 279 

covered with fine coal and coke dust, and tightened that also to 
stop the draft in that direction. The object in using coal dust 
was this: should any get through into the charges, it would not 
cause much trouble. After all was completed, gave orders to 
the cupola «men to be on hand at 6 a. m. next morning, clean 
out the tuyeres and top of cupola, and ordered the men to be 
ready for pouring off at 7 a. m. The next morning all were on 
time. I had the tuyeres poked with bars, so that the blast 
might have easy access to center of cupola, and started the 
blast at 7 : 15, bottom being dropped at 8 : 45 ; total time from 
time of lighting cupola until bottom dropped, was nineteen 
hours. At first the iron was long in coming down and first 500 
lbs. somewhat dull, but made provision for that and put it into 
dies, which turned out to be very good. The balance of the 
heat was hot enough for any kind of casting — our line being light 
and heavy, and had to be planed, bored and otherwise finished 
with some stove repair casting in with this heat engine casting, 
cylinder and a class of work that requires fluid metal. I am 
confident that if this method is carefully followed, it can be done 
at all times, but would not advise it in small cupolas, less than 
36" inside measurement; and should the melt be in progress, it 
could not be successfully done at all. Should I be placed in a 
similar position, would resort to the same means with more con- 
fidence and certainty of success. 

"Yours respectfully, 

John C. Knceppel, 
Foundry Siipt. Buffalo Forge Co., Biffalo, N. Y. 

BLAST PIPES. 

In constructing a cupola, one of the most important points to 
be considered is the construction and arrangement of blast pipes 
and their connection with the cupola, for the best constructed 
cupola may be a complete failure through bad arrangement of 
pipes and air-chambers. 

Not many years ago it was a common practice of foundry- 
men to place blast pipes underground. The main pipe was 



280 THE CUPOLA FURNACE. 

generally made square and constructed of boards or planks 
spiked together, no care being taken to make air-tight joints, 
and the escape of blast was prevented by ramming sand or clay 
around the pipe when put in place. Connections from the 
main pipe to the cupola were made by means of vertical cast- 
iron pipes to each tuyere, as shown in Figs. 31 and 32. The 
main pipes were generally constructed with square elbows and 
ends, and the tuyere pipes were placed over an opening in the 
top of a branch of the main pipe on each side of the cupola. The 
square turns and ends of the pipe greatly reduced the force of 
the blast, and the capacity of the pipe was frequently reduced 
by water leaking into it or a partial collapse of the pipe, and 
the volume of blast delivered to a cupola was very uncertain 
even when the pipes were new, and could not be depended upon 
at all when the pipes became old and rotten. Iron pipes ar- 
ranged in this way were also a source of continual annoyance 
and uncertainty from water or iron and slag from the tuyeres 
getting into them and reducing their capacity for conveying 
blast. This way of arranging cupola pipes has generally been 
abandoned, and they are now commonly placed overhead or 
up where they are least liable to injury and may be readily 
examined to see that there is no leakage of blast from a pipe. 
Blast pipes may be made of wood, tin plate, sheet iron, cast 
iron, or galvanized iron. Wooden pipes shrink and expand 
with changes of weather and moisture in the atmosphere, and it 
is almost impossible to prevent the escape of blast from such 
pipes. Tin and sheet iron pipes, when placed in a foundry, are 
very rapidly rusted and destroyed by steam and gases escap- 
ing from moulds and the cupola, if not thoroughly painted out- 
side and in. Cast iron pipes are heavy, difficult to support in 
place, liable to break when not properly supported, or leak at 
the joints, and the best for foundry use are those made of gal- 
vanized iron. In constructing pipes of this material, an iron of 
a proper gauge for the size of pipe should be selected, and their 
shape should, whenever possible, be round, for round pipes are 
more easily constructed and have the largest effective area with 



TAKING OFF THE BLAST DURING A HEAT. 28 1 

a given perimeter of any known figure. Pipes should be made 
in lengths convenient for handling, say 8 or lo ft., having joints 
lapped nearly 2 inches in direction of the air current. Joints 
should be riveted about every 4 inches to hold them securely 
together and prevent sagging of the pipe between supports, and 
to insure their being tight they should be soldered all the way 
around. Section ends should be placed over supports and 
laps of from 3 to 4 inches made at each joint and also soldered. 
The end of the main pipe when not connected direct with an 
air chamber on the cupola should be divided into two or more 
branches of equal capacity for connection with the tU3'eres or 
air belt, and rounded curves or elbows used in changing the 
direction of pipes. A pipe should never terminate abruptly, 
and branches should not be taken out of the side for supplying 
the cupola, as is frequently done. The area of main pipes and 
also branch pipes should be increased as the distance from the 
blower to the cupola is increased ; and as a guide for increasing 
their diameter in proportion to the length of pipe, we do not 
think we can do better than give our readers the excellent 
table prepared by the Bufifalo Forge Co., Buffalo, N. Y., as 
follows. 

DIAMETER OF BLAST PIPES, 

It will be seen, by reference to the following table, that the 
diameter of pipe for transmitting or carrying air from one point 
to another, changes with the length or distance which the air 
is carried from the blower tq the furnace, or other point of 
delivery. 

As air moves through pipes, a portion of its force is retarded 
by the friction of its particles along the sides of the pipe, and 
the loss of pressure from this source increases directly as the 
length of the pipe, and as the square of the velocity of the 
moving air. 

This fact has long been known, and many experimenters 
and engineers, by close observation and long-continued experi- 
ments, have established formulas by which the loss of pressure 



282 THE CUPOLA FURNACE. 

and the additional amount of power required to force air or 
gases through pipes of any length and diameter may be 
computed. 

As these formulas are commonly expressed in algebraic 
notation, not in general use, we have thought it desirable to 
arrange a table showing at a glance all the necessary propor- 
tionate increase in diameter and length of blast pipes and 
conical mouth-pieces, in keeping up the pressure to the point 
of delivery. It is often the case, where a blower is C07identned 
as being insufficient, the cause of its failure is that the pipe 
connections are too small for their lengths, coupled with 
a large number of short bends, without regard to making 
the pipe tight, which is a necessity. 

The table, diameter of pipes, given below, showing the 
necessary increase in the size of pipes in proportion to the 
lengths, is what we call a practical one, and experience has 
proved the necessity for it. 



TAKING OFF THE BLAST DURING A HEAT. 



283 



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284 THE CUPOLA FURNACE. 

The connection of blast pipes with cupolas is also a matter 
to which entirely too little attention is given, and is frequently 
the cause of poor melting when cupola is otherwise properly 
constructed. As stated elsewhere, tuyeres should be large 
enough to admit blast to a cupola freely, and to obtain good 
results in melting it must be fully and evenly distributed to 
the tuyeres. When blast is delivered direct to tuyeres through 
branch pipes, the branches should be taken ofT the main pipe 
in as near a direct line with the current of the blast in the 
mainpipe as possible, and its course to the tuyeres should be 
changed by long curves or round elbows in the pipes, to pre- 
vent the velocity of the air being checked and blast thrown 
back in the pipe. The combined area of all the branch pipes 
should be equal to the area of the main pipe and not less as is 
frequently the case, owing to a mistake being made through 
the erroneous idea that a multiple of the diameter of two or 
more small pipes is equal to the area of one large one of 
their combmed diameters. If this were the case two five-inch 
pipes would have an area equal to one ten-inch pipe, which is 
not so, as will be seen by the table on p. 285, which may be of 
value to foundrymen in arranging their blast pipes. 



i 



TAKING OFF THE BLAST DURING A HEAT. 



285 



DIAMETER AND AREA OF PIPES. 



Diameter. 


Area. 


Diameter. 


Area. 


Diameter. 
I4>^ 


Area. 


2 


3-141 { 


8M 


53-456 


165.13 


' 2^4 


3.976 1 


8>^ 


56-745 


14^ 


170.85 


^% 


4.908 


8% 


60.132 


15 


176.71 


2% 


5-939 i 


9 


63.617 


i5?4 


182.65 


3 


7.068 1 


9)^ 


67.2CO 


I5>2^ 


188.69 


ZVa 


8.295 


9>^ 


70.882 


15% 


194.82 


1% 


9.621 


9K 


74.662 


16 


201.06 


M 


11,044 


10 


78.539 


I6>'4 


207.39 


4 


12.566 


10I4 


82.516 


16)2 


213.82 


4>i 


14.186 


loi. 


86.590 


16% 


220.35 


4>^, 


15.904 


I03.' 


90.762 j 


17 


226.98 


4% 


17.720 


II 


95.033 i 


17k 


233-70 


5 


19-635 


"M 


99.402 


^1% 


240.52 


5J4 


21.647 


nfo 


103.86 


11% 


247-45 


5K 


23-758 


1 1^1 


108.43 


18 


254.46 


sK 


25.967 


12 


"3.09 


18)4 


261.58 


6 


28.274 


I2>4 


117.85 


i8>^ 


268.80 


6M 


30.679 


I2l^ 


122,71 


18% 


276.11 


6K 


33-i«3 


12^ 


127.67 


19 


283.52 


6K 


35-784 


13 


132-73 i 


19k' 


291.03 


7 


38.484 


13^4 


137.88 , 


I9>^ 


298.64 


7Ji 


41.282 


I3M 


143-13 


19^ 


306.35 


7>^. 


44.178 


13% 


148.48 


20 


314.16 


7?4 


47-173 


14 


153-93 ' 








50.265 


I4M 


159-48 1 







286 THE CUPOLA FURNACE. 

In connecting blast pipes direct with tuyeres, either by long 
branch pipes from the main pipe or short ones from a belt air 
chamber not attached to cupola shell, care should be taken to 
have as few joints or connections in the pipes as possible, and 
every joint should be made in such a way that the jar made in 
chipping out and charging the cupola will not cause the joints 
to leak after they have been in use a short time. In leading 
pipes out of an air chamber they cannot always be placed in 
line with the current of the blast, and must be filled from pres- 
sure of blast in the air chamber, but the ciDnnecting pipes may 
be shaped to guide the blast smoothly from the air chamber to 
its destination. 

In Fig. 56 is shown as perfect a connection of air chambers 
of this kind as can be made. In this illustration the belt pipe 
A A is placed up out of the way and of danger of being injured 
when making up or working the cupola, and the branch pipes 
to each tuyere are straight and smooth inside and the pipe is 
given a curve at the bottom to throw the blast into the tuyere 
without having the force of its current impaired, and the tuyeres 
arc of a size to admit the full volume of blast from the pipe. 
Only two joints are required in connecting the air chamber with 
the cupola, and these are made in such a way that they may be 
securely bolted or riveted, and all leakage prevented. 

In contrast with the neat arrangement of pipes on this cupola 
is shown the other extreme of poor arrangement in illustration 
Figure 59. This is a section of a "perfect cupola" illustrated 
and described in T/ie Iron Age some years ago, and while other 
parts of the cupola may have been perfect, this part was cer- 
tainly very imperfect. The air chamber and its connecting 
pipes are made of cast iron. The connecting pipes are cast in 
three pieces, necessitating the making of four joints. The air 
box is cast in two pieces, requiring another joint ; and a peep- 
hole and an opening for escape of slag and iron running into 
the tuyeres, is placed in the pipe, making in all seven joints and 
openings in each connection to be made and kept air-tight. 
The jar in working the cupola, together with the small explo- 



TAKING OFF THE BLAST DURING A HEAT. 28/ 

sions of gas that frequentl}' take place in cupolas and pipes, 

Fig. 59. 




POOR ARRANGEMENT OE BLAST PIPES. 



would naturally tend to loosen many of these joints, and a large 



288 THE CUPOLA FURNACE. 

amount of blast would be lost through leakage of joints. The 
many joints make more or less roughness in the pipes, thus im- 
peding the blast. The turn in the pipe for connection with the 
tuyere is square and the course of the current of air is abruptly 
changed, and the tuyere is entirely too small to admit the full 
volume of blast from the pipe to the cupola, and only by a 
heavy pressure of blast could the air be forced into the cupola 
in sufificient quantities to do good melting. 

In Fig. 57 is shown another way of connecting a belt air- 
chamber with the tuyeres. In this case the pipe is made of 
galvanized iron, and the tuyere boxes are made of cast-iron and 
are large, giving abundant room for changing the direction of the 
blast current. Only two joints are made in connecting the air- 
chamber with the cupola ; beside these joints, the end of the 
tuyere box is closed with a large door, the full size of the box, 
and a peep-hole is placed in the door, making two more open- 
ings to be kept air-tight. Many cupolas are in use having their 
blast connections arranged in this way, and while the arrange- 
ment is very good, it is not perfect, and a great deal of blast is 
lost through leakage of joints — the principal loss occurring 
around the large door and at the joint connecting the galvan- 
ized iron pipe with the cast-iron tuyere box. 

The very best way of connecting blast pipes with cupola tuy- 
eres is by means of a belt air-chamber riveted to the cupola cast- 
ing, as shown in Figs. 39, 43 and 45, or by an inside air-chamber, 
as shown in Figs. 3 i and 46. In either case the air-chamber is 
riveted to the cupola shell and the joint made perfectly air-tight, 
and in case of jar to the cupola, the air-chamber being part of 
the cupola, oscillates with it, and the jar in chipping out and 
charging does not loosen the joint and cause leakage of blast. 
The blast pipes may also be securely riveted or bolted to the 
air-chamber and a perfectly tight joint made. In constructing 
cupolas in this way, care should be taken to make the air- 
chamber of a sufificient size to admit of a free circulation of 
blast and supply all the tuyeres with an adequate amount for 
good melting. When the air-chamber is small, the blast pipe 



TAKING OFF THE BLAST DURING A HEAT. 



289 



should be connected with it on each side of the cupola, and 
on the side or top as found most convenient. When the 
chamber is large and there is an abundance of room for the 
escape of blast from the pipe, one pipe is sufficient and it 
may be connected on the side or top. When attached on the 
side it should be placed in line with the circle of the cupola as 
shown in Fig. 48, to cause the current of blast to circulate 
around the cupola and facilitate its escape from the pipe. When 

Fig. 60. 




BLOWER PLACED NEAR CUPOLA. 



the current of blast is thrown directly against the cupola casing 
or bottom of the chamber in a narrow air-chamber, the mouth 
of the pipe should be enlarged, to facilitate the escape of blast 
into the chamber; for cupolas of this construction may be made 
a complete failure by failing to provide a sufficient space at the 
end of the pipe for escape of blast into the air-chamber, when 
the chamber is of a sufficient size to supply the cupola. Con- 
nections with the inner air-chambers of limited capacity should 
19 



290 THE CUPOLA FURNACE. 

be made on each side by means of an air or tuyere box placed 
outside as shown in Fig. 6, and the pipe connected on top to 
equaHze the volume of blast supplied to each tuyere. 

Long blast pipes often cause poor melting, from the volume 
of blast delivered to a cupola, being reduced by friction in the 
pipes, and in all cases the blower should be placed as near the 
cupola as possible. In Fig. 60 is shown a very neat arrange- 
ment in placing a blower near a cupola and at the seme time 
having it up out of the way of removing molten iron or the 
dump from the cupola, and the space under it may be utilized 
for storing ladles, etc. In this illustration is also shown a very 
perfect manner of connecting the main pipe with an air 
chamber. The pipe is divided into two branches of equal 
size in line with the current of blast from the blower, and con- 
nected with the air chamber on each side by curved pipes 
arranged in such a way as not to check the current of air as it 
passes through the pipe. 

BLAST GATES. 

These devices are especially designed for opening and clos- 
ing blast pipes, such as are employed for conveying air be- 
tween blowers and cupolas. There are several different 
designs of blast gates, but the one shown in Fig. 61 is the one 
most commonly used by foundrymen. They are manufactured 
and kept in stock by all the leading manufacturers of blowers, 
and cost from one dollar upwards, according to size of blast 
pipe. 

The employment of the blast gate places the volume of 
blast delivered to a cupola under control of the melter, which 
feature is frequently very important in the management of 
cupolas in melting fron for special work, or in case of accident 
or delay in pouring. In foundries in which the facilities for 
handling molten metal are limited and melting must at times 
be retarded, to facilitate its removal from the cupola as fast as 
melted, and in foundries where the amount of iron required to 
be melted per hour is limited by the number of molds or chills 



TAKING OFF THE BLAST DURING A HEAT. 



291 



employed, from which castings are removed and the molds re- 
filled, it is very important that the blast should be under con- 
trol of the melter. In such foundries the cupolas are generally 
of small diameter and frequently kept in blast for a number of 
hours at a time, and it is often desired to increase the volume 
of blast to liven up the iron and decrease it, to reduce the 
amount melted in a given time. 

The blast gate places the blast under control of the melter 
and enables him to increase or diminish its volume as deemed 

Fig. 61. 




BLAST GATE. 



necessary to obtain the best results in melting. They are 
often of value in regular cupola practice to reduce the volume 
of blast and retard melting for a few minutes while pouring a 
large piece of work, in foundries where the facilities for hand- 
ling large quantities of molten iron are limited, and the speed 
of blower cannot be reduced without reducing the speed of 
machinery in other parts of the works or stopping the blower, 
entirely, which is not good practise after a cupola has been in 
blast for some time. 



292 THE CUPOLA FURNACE. 

The gate is also a safeguard against gas explosions, which 
often occur from the accumulation of gas in pipes during the 
temporary stoppage of the blower. The gate should always 
be placed in the pipe near the cupola, and closed before stop- 
ping the blower and not opened until it is again started up. 

EXPLOSIONS IN BLAST PIPES. 

Violent explosions frequently take place in cupola blast pipes^ 
tearing them asunder from end to end. These explosions are 
due to the escape of gas from the cupola into the pipes during 
a temporary stoppage of the blower in the course of a heat. The 
explosion is caused by the gas being ignited when the pipe 
becomes over-charged, or the instant the blower is started and 
the gas is forced back into the cupola. Such explosions gen- 
erally take place in pipes placed high or arranged in such away 
as to have a draught toward the blower. But they may occur 
in any pipe if the cupola is well-filled when a stoppage takes 
place and the blower is stopped for a great length of time. 

Such explosions may be prevented by closing the blast-gate 
if placed near the cupola, or by opening the tuyere doors 
in front of each tuyere and admitting air freely to the pipe. 
Such precaution should always be taken the instant the blast is 
stopped, as a pipe may be exploded after only a few minutes' 
stoppage of the blower, and men may be injured or the blower 
destroyed by the explosion. 

BLAST GAUGES. 

A number of air or blast gauges have been designed and 
placed upon the market for determining the pressure of blast in 
cupola blast pipes and air-chambers. These gauges are of a 
variety of design, and are known as siecl spring, water and mer- 
C7iry gauges. They are connected with a blast pipe or air- 
chamber by means of a short piece of gas-pipe or a piece of 
small rubber hose, through which the air is admitted to the 
gauge. The pressure of blast is indicated by a face dial and 
hand on the spring gauge, and the graduated glass tube of the 



TAKING OFF THE BLAST DURING A HEAT. 293 

water and mercury gauges, pressure being shown up to two 
pounds, in fractions of an ounce. These gauges, when in good 
order, indicate very accurately the pressure of blast on a cu- 
pola, and when tuyeres and pipes are properly arranged, show 
to some extent the resistance ofifered to the free escape of blast 
from the pipe and the condition of the cupola in melting. But 
they do not indicate the number of cubic feet of air that pass 
into a cupola in any given length of time, and a gauge may 
show a pressure of six or eight ounces when scarcely a cubic 
foot of air is passing into a cupola per minute. 

With a pressure blower these gauges show a gradual increase 
of pressure in the pipe when a cupola is clogging up, and may 
enable a foundryman to prevent bursting of the pipe ; but with a 
none-positive blower they show nothing that is of any value to 
a foundryman in melting, so far as we have been able to learn. 
The volume of blast is what does the work in a cupola, and not 
the pressure ; and a high pressure of blast does not always indi- 
cate a large volume of blast, but rather the reverse, for little if 
any pressure can be shown on a gauge when blast escapes 
freely from a pipe. 

We have seen two cupolas of the same diameter, one melting 
with a two-ounce pressure of blast and the other with a six- 
qunce pressure, and the cupola with the low pressure doing the 
best melting. This was simply because with the low pressure 
the air was escaping from the pipe into the cupola and 
with the high pressure it was not, and the high pressure was 
wholly due to the smallness of the tuyeres which prevented the 
free escape of blast from the pipe into the cupola. 

A definite number of cubic feet of air has been determined by 
accurate experiments to be required to melt a ton of iron in a 
cupola, and an air-gauge to be of any value in melting must indi- 
cate the number of cubic feet of air that actually enter a cupola 
at the tuyeres. We have at the present time no such gauge, 
and in the absence of such a gauge the foundryman's best 
guide as to the number of cubic feet of air supplied to his 
cupola is the tables furnished by all manufacturers of standard 



294 THE CUPOLA FURNACE. 

blowers, giving the number of revolutions at which their blowers 
should be run, and the number of cubic feet of air delivered at 
each revolution. From these tables a foundryman may figure 
out the exact number of cubic feet of air his cupola receives, 
provided there is no leakage of air from pipes or tuyeres and 
the tuyeres are of a size that will permit the air to enter the 
cupola freely. 

BLAST IN MELTING. 

A cupola furnace requires a large volume of air to produce 
a thorough and rapid combustion of fuel in the melting of iron 
or other metals in the furnace. Numerous means have been 
devised for supplying the required amount of air, among them 
the draught of a high chimney or stack, and the creating of a 
vacuum in the cupola by means of a steam jet, placed in a con- 
tracted outlet of a cupola as shown in Figs. 28 and 29. These 
means of supplying air are a success in cupolas of small 
diameter and limited height, but even in these cupolas the 
volume of air that can be drawn in is not sufificient to produce 
rapid melting, and it is doubtful if iron could be melted at all 
in a cupola of large diameter and of a proper height to do 
economical melting, by either of these means of supplying air. 
Owing to the peculiar construction of a cupola furnace and the 
manner of melting, the free passage of air through it is rcr 
stricted by the iron and fuel required ; and rapid melting can 
only be done when air for the combustion of the fuel is sup- 
plied in a large volume, which can only be by a forced blast. 

A number of machines have been devised for supplying this 
blast, among the earliest of which were the leather bellows, 
trompe or water blast, chain blast, cogniardelle or water-cylin- 
der blast, cylinder or piston blower. These have, as a rule, given 
away to the more modern fan blower and rotary positive blast 
blower, a number of which will be described later on. 

The relative merits of a positive aud non-positive blast, is a 
very much disputed question. It is claimed by many, that 
with a positive blast a definite amount of air is supplied to 
a cupola per minute or per hour, while with a non-positive 



TAKING OFF THE BLAST DURING A HEAT. 295 

blower or fan there is no certainty as to the amount of air the 
cupola will receive. This is very true, for a cupola certainly 
does not receive the same amount of air from a fan blower when 
the tuyeres and cupola are beginning to clog as it does from a 
positive blower when there is n^ slipping of the belts. But is 
it advisable to supply a cupola with as large a volume of blast 
when in this condition as when working open and free? 
Does not the large volume of blast have a chilling effect upon 
the semi-fluid mass of cinder and slag, and tend to promote 
clogging about the tuyeres while keeping it open above the 
tuyeres ; while blast from a non-positive blower would perculate 
through small openings in the mass, and be more efTective than 
a large volume of blast from a positive blower forming large 
openings in it through which it escaped into the cupola? 

These are questions we have frequently tried to solve by 
actual test ; but it is so diflficult to find two cupolas of the same 
dimensions melting the same sized heats for the same class of 
work, one with a positive and the other with a non-positive 
blast, that we have never been able to test the matter. We have 
melted iron with nearly all the blowers now in use and with a 
number of the old-style ones, and think there is more in the 
management of a cupola than there is in a positive or non- 
positive blast. Good melting may be done with either of them, 
when the cupola is properly managed, and it cannot be done 
with either of them when the cupola is not properly managed. 
Until the management of cupolas in every-day practice is re- 
duced to more of a system than at present, it will be impossible 
to determine any practical advantage in favor of either blower 
over the other. So far as we are concerned, we have no prefer- 
ence in blowers, but make it a rule to charge a cupola more 
openly when melting with a non-positive blast, for the reason 
that stock may be packed so closely in a high cupola, that the 
volume of blast that is permitted to enter at the tuyeres may 
not be reduced by preventing its escape through the stock. 

The amount of air that is required for combustion of the fuel 
in melting a ton of iron has been determined by accurate ex- 



296 THE CUPOLA FURNACE. 

periments to be about 30,000 cubic feet, in a properly con- 
structed cupola in which the air was all utilized in combustion 
of the fuel. This amount of air if reduced to a solid would 
weigh about 24,000 lbs., or more than the combined weight of 
the iron and fuel required to melt it. In a cupola melting ten 
tons per hour, 300,000 cubic feet of air must be delivered to>the 
cupola per hour to do the work. It will thus be seen, that a 
very large volume of blast is required in the melting of 10 tons 
of iron. To deliver this amount of air to a cupola from a 
blower that is capable of producing it in the shape of a blast, 
the blast pipes must be arranged in such a way that the velocity 
of the air is not impeded by the pipes ; and the tuyeres must 
be of a size to admit the air freely to the cupola. This is not 
always the case, for we have seen many cupolas in which the 
combined tuyere area was not more than one-half that of the 
blower outlet The object in making the tuyere area so small 
was to put the air into the cupola with a force that would drive 
it to the center of the stock. This was the theory of melting in 
the old cupolas with small tuyeres, but this is wrong, for air 
cannot be driven through fuel in front of a tuyere, as an iron 
bar could be forced through it, even with a positive blast; and 
when the air strikes the fuel it cannot pass through it, but 
escapes through the crevices between the pieces of fuel. These 
crevices may change its direction entirely, and the same force 
that drives it into the cupola impels it in the direction taken, 
which will be the readiest means of escape, and is more liable 
to be up along the lining than toward the center of the cupola. 
For, as a rule, stock does not pack so close near the lining as 
toward the center, and the means taken to prevent the escape 
of blast around the lining is the very thing that causes it to 
escape in that way. Since blast cannot be driven through fuel 
to the center of a cupola and can only escape from the tuyeres 
through the crevices between the pieces of fuel, the only way to 
force it to the center of a cupola is to supply a sufificient volume 
of blast to fill all of the crevices between the pieces of fuel. 
This can only be done by discarding the small tuyeres and 
using a tuyere that will admit blast freely to a cupola. 



TAKING OFF THE BLAST DURING A HEAT. 297 

In placing tuyeres in a cupola, it must be remembered that the 
outlet area of a tuyere is governed by the number of crevices 
between the pieces of fuel in front of the tuyere through which 
the blast may escape from the tuyere. With small tuyeres a 
large piece of fuel may settle in front of the tuyere in such a 
way that the tuyere outlet is not equal to one one-hundreth 
part of the tuyere area, in which case the tuyere is rendered 
useless, and may remain useless throughout the heat. For 
these reasons small tuyeres should never be placed in a cupola. 
For small cupolas we should recommend the triangular tuyere, 
Fig. 14, for the reason that it tends to prevent bridging, and its 
shape is such that it is less liable to be closed by a large piece 
of fuel than a round tuyere of equal area. The vertical slot 
tuyeres, Figs. 10 and 1 1, are also for the same reason good tuy- 
eres for small cupolas. 

For large cupolas we think the expanding tuyere, Fig. 3, is 
the best, and if we were constructing a large cupola we should 
use this tuyere in preference to any other, and make the out- 
let at least double the size of the inlet, and should place the tuy- 
eres so close together that the outlets would not be more than 
six or eight inches apart. This would practically give a sheet 
blast, and distribute air evenly to the stock all around the 
cupola. The width of the tuyere can be made to correspond 
with the diameter of cupola, and may be from three to six 
inches, and should be of a size that will permit blast freely to 
enter the cupola. Parties who have been melting with small 
tuyeres and put in large ones upon this plan, must change their 
bed and charges to suit the tuyeres, for this arrangement of 
tuyeres would probably be a complete failure in a cupola charged 
in the same way as when not more than one-fourth of the blast 
supplied by the blower entered the cupola. 

The largest cupolas in which air can be forced to the center 
from side tuyeres with good results would appear from actual 
test to be from four and a half to five feet. Larger cupolas 
than this have been constructed, and are now in use, but they 
do not melt so rapidly in proportion to their size as those of a 



298 THE CUPOLA FURNACE. 

smaller diameter. To illustrate this, we might cite the Jumbo 
Cupola of Abendroth Bros., Port Chester, N. Y., already de- 
scribed, in which the the diameter at the tuyeres is 54 inches, 
and above the bosh 72 inches, in which 15 tons of iron have 
been melted per hour for stove-plate and other light castings. 

The Carnegie Steel Works, Homestead, Pa., have cupolas of 
seven and one-half feet diameter at the tuyeres and ten feet di- 
ameter above the bosh, in which the best melting per hour is 
only fourteen tons. The area of this cupola at the tuyeres is 
almost three times that of Abendroth's cupola, yet the amount of 
iron melted per hour is actually less than that of the smaller 
cupola. Tuyeres have been arranged in different ways in this 
large cupola, and from one to four rows used, yet the melting was 
not in proportion to the size of cupola. This would seem to 
indicate that the cupola was not properly supplied with blast 
near the centre, and the melting done in the center was caused 
principally by the heat around it ; which is probably the case, 
for the cupola is kept in blast night and day, for six days, and 
melting must take place in the centre, or the cupola would 
chill up. 

There are many cupolas of sixty inches diameter at the 
tuyeres in use in which good melting is done, but this would 
seem to be the limit at which good melting takes place in a 
cupola supplied with blast from side tuyeres, for above this di- 
ameter the rapidity of melting does not increase in proportion 
to the increase in size of cupola. 

There has been considerable experimenting done during the 
past two or three years with a center blast tuyere for admitting 
blast to the center of a cupola through the bottom. We have 
had no practical experience with this kind of tuyere for the last 
twenty-five years, when we placed one in a small cupola with 
side tuyeres and found no advantage in it; probably for the 
reason that a sufficient quantity of air for an even combustion 
of the fuel was supplied to the centre of the cupola from the 
side tuyeres. 

During the past few years, we have visited a number of foun- 



TAKING OFF THE BLAST DURING A HEAT. 299 

dries in which the center blast was being tried, but in every 
case the tuyere was out of order or not in use at the time of 
our visit. The great objection to this tuyere seems to be its 
liability to be filled with iron or slag and rendered useless. 
Should this objectionable feature be overcome by such practical 
foundrymen as Mr. West or Mr. Johnson, who are experiment- 
ing with centre blast, it would certainly be a decided advantage 
in melting in cupolas of large diameter, in connection with side 
tuyeres. In cupolas of small diameter with side tuyeres, we do 
not think a center blast would increase the melting capacity of 
a cupola, for the reason that air can be forced to the center of 
a small cupola from side tuyeres, when properly arranged and 
of a proper size. 

With a center blast alone, it is claimed that considerable sav- 
ing is effected in lining and fuel. It is reasonable to suppose 
that a saving in lining might be effected by a centre blast; for 
the most intense heat that is created by the blast is transferred 
from near the lining to the center of the cupola, and the tend- 
ency to bridge is greatly reduced. As to the saving of fuel, 
there never was a new tuyere that did not " save fuel," and there 
have been hundreds of them, but consumption of cupola-fuel 
is still too large. 



CHAPTER XXI. 



BLOWERS. 



PLACING A BLOWER. 



A BLOWER should always be placed at as near a point to a 
cupola as is consistent with the arrangement of the foundry- 
plant, and it should be laid upon a good, solid foundation, and 
securely bolted to prevent jarring, as there is nothing that 
wrecks a blower so quickly as a continual jar when running at 
high speed. In Fig. 60 is shown a convenient way of placing 
a blower near a cupola, aud at the same time having it out of 
the way. But when so placed, the blower should be laid 
upon a solid frame-work of heavy timber, and securely bolted 
down to prevent jarring when running. It should also be 
boxed in to prevent air being drawn in from the foundry, and 
have an opening provided for supplying air from the outside, 
for air drawn from a foundry when casting and shaking out are 
taking place is filled with dust and steam, which are very injur- 
ious to a blower and pipes. 

A blower should never for the same reason be placed in a 
cupola-room or a scratch room in which castings are cleaned ; 
for it is impossible to exclude dust from the bearings when so 
placed, and when a bearing once begins to cut, it makes room for 
a greater amount of dust, and cuts out very rapidly in blowers 
run at high speed. Dust and steam also corrode and destroy 
blast wheels which are inside the blower and out of sight, and a 
blast wheel may be almost entirely destroyed and not discov- 
ered until it is found the cupola is receiving no blast. To pre- 
vent a blower from being destroyed in this way, and insure a 
proper volume of blast for a cupola, the blower should be placed 
in a clean, dry room and supplied with pure air from the outside. 

( 300) 



BLOWERS. 



301 



If it cannot be so placed near a cupola, it had better be placed 
at some distance, in which case the blast pipe must be enlarged 
in proportion to its length, as described elsewhere. When a 
blower is placed in a closed room, windows should be opened 
to admit air when it is running, and when the air about the 
room is filled with dust, a pipe or box for supplying pure air 
should be run off to some distance from the blower and the 
room kept tightly closed. 

FAN BLOWERS. 

BUFFALO STEEL PRESSURE BLOWER.* 

The manufacturers make claim for their blower as follows ; 
In Fig. 62 is shown the latest improved construction form of 

Fi<;. 62. 




STEFX PRESSURE BLOWER. 



the BufTalo Steel Pressure Blower, for cupola furnaces and forge 
fires. A distinguishing feature of this blower, common to 

* Manufactured by Buffalo Forge Co., Buffalo, N. Y. 



302 THE CUPOLA FURNACE. 

those of no other manufacture of the same type, is the solid 
case, the peripheral portion of the shell being cast in one solid 
piece, to which the center plates are accurately fitted, metal to 
metal. It will thus be seen that the objectionable and slovenly 
" putty joint" is entirely dispensed with. Ready access to the 
interior of the blower, without entirely taking it apart, is also 
thus afforded. With blowers of other manufacture, the " putty 
joint" feature of the shell or casing is an indispensable adjunct, 
although it is a construction point vvhich is, at the best, some- 
thing to be avoided in an efficient machine. 

The Bufifalo Steel Pressure Blower is designed and con- 
structed especially for high pressure duty, such as supplying 
blast for cupolas, furnaces, forge fires, sand blast machines, for 
any work requiring forcing of air long distances, as in connec- 
tion with pneumatic tube delivery system. It is adapted for 
all uses where a high pressure or strong blast of air is re- 
quired. The journals are long and heavy, in the standard 
ratio of length to diameter of six to one, and embody a greater 
amount of wearing surface than those upon the blower 
of any other construction. Attention is directed to the pat- 
ented journals and oiling devices employed on this blower, 
which are unique features. The bearings are readily adjustable, 
and any wear can be taken up, which is an important point at- 
tending the durability and quiet running of a perfect machine. 

The Bufifalo Steel Pressure Blower possesses the fewest number 
of parts of any like machine ; in fact, the blower is practically 
one piece, so that under any service the bearings invariably are 
in perfect alignment, vertically and laterally, with the rest of the 
machine. In the items of durability, smooth running and 
economy of power, it is thus rendered far superior to any 
blower with the so-called universal journal bearing which is 
commonly employed. 

In every point of construction, the greatest pains have been 
taken to simplify all parts and at the same time to give them 
the greatest strength. To adjust, repair and keep in order a 
Buffalo Blower is a very small matter and readily understood 
by a machinist of average ability. 



BLOWERS. 303 

For obtaining the best results from a blower of given size, 
when used for melting iron in foundry cupolas, much depends 
upon the proper lay-out of the blast piping between the blower 
and the cupola, and also upon the proper proportionment, ar- 
rangement and design of the cupola tuyeres, Several forms of 
cupolas are now upon the market, economical in the use of fuel 
and fast melting, which are the points most sought for in cupola 
construction. It is a common but erroneous idea that a blower 
large for the work will give better results, in a given diameter 
of cupola, than a smaller one. In the tables which accompany 
the blower, we give the proper sizes of blower for different 
diameters of cupolas ; but it must be borne in mind, that if the 
tuyerage is not of sufificient area, or if the blower has to be 
located at some distance from the work to be accomplished, 
these points enter for consideration. Frequently, foundrymen, 
when experiencing difficulty in obtaining satisfactory melts, 
throw the whole cause of the trouble upon the blower, when 
the fault does not lie at this point. It is safe to say that failures 
are due more largely to the mismanagement of a cupola and 
improper application of the blower, than to any other cause. 

The Buffalo Steel Pressure Blower is especially adapted for 
foundry cupolas, and is guaranteed to produce stronger blast 
with less expense for power, than any other. 

BLOWER ON ADJUSTABLE BED, AND ON BED COMBINED WITH COUNTERSHAFT. 

Unless considerable care is taken in putting up countershafts, 
and some special attention is given to keep them in perfect 
alignment, trouble is often experienced, especially in keeping 
the belts on the larger sizes of blowers, on account of the great 
speed at which they have to run to produce high pressures. To 
overcome such features, this house designed the adjustable bed, 
and the adjustable bed combined with countershaft arrange- 
ments, which is illustrated in Fig. 63. The blower on adjust- 
able bed, alone, without Ihe countershaft, is very convenient 
for taking up the slack in belts while the fan is in motion and 
driven by belt from main line. 



304 



THE CUPOLA FURNACE. 



In Fig. 63 is shown the latest construction form of BufTalo 
Steel Pressure Blower on adjustable bed with combined counter- 
shaft. Its use will be found to result in a decided saving in the wear 
and tear upon belts, which, in a short time, more than justifies 
the extra initial expense of the arrangement. The cost will be 
found little in excess of ordinary method, and a few turns of the 
nut on the end of the adjusting screw, which is clearly shown 
directly under the outlet of the blower, after first unloosening 
the holding' down bolts,which should afterward be re-tightened, 

Fig. 63. 




BLOWER AND COUNTERSHAFT. 



accomplish, in a very few moments, what, previous to the intro- 
duction of this apparatus, has caused considerable delay and 
annoyance. It will readily be seen that the usual frequent re- 
lacing of belts, to make them sufificiently tight to avoid slipping, 
is hereby entirely obviated. 

Positive alignment of the countershaft with the shaft of the 
blower by this arrangement causes the belt to track evenly, run 
smoothly and avoid the usual wear by their striking against the 
hanger or side of the blower. As will be readily appreciated, 
the tightening screw gives the same uniform tension to both 



BLOWERS. 305 

belts, and this may be regulated at will of operatior. A tele- 
scopic mouth-piece, as is shown by the cut, is placed upon each 
blower purchased in this form, which enables the machine to 
be moved upon its bed without any disarrangemnnt of the. 
blast piping. 

Especial attention is called to the fact that the arrangement 
of blower on adjustable bed combined with countershaft, as il- 
lustrated in Fig. 63, occupies the smallest amount of space 
consumed by any apparatus of this kind manufactured in the 
world. Ordinary tight and loose pulleys are placed upon the 
countershaft from which the power is transmitted to the counter- 
shaft of this apparatus. When this feature is not desirable, 
which is often the case where power is transmitted from the 
main line without the intervention of a countershaft, the adjust- 
able bed countershaft may be furnished with the blower, so 
that it will extend at the right or left, as desired, and the tight 
and loose pulleys are then placed thereon ; we then have a 
right or left hand apparatus. The space between the two pul- 
leys which drive the blower is not wide enough to permit of 
the introduction of tight and loose pulleys. 

BLOWER ON ADJUSTABLE BED, COMBINED WITH DOUBLE UPRIGHT ENGINE. 

We would call attention to the blower in the adjustable bed 
form and also in the combination with countershaft. The 
further combination as secured in the introduction of a double 
upright enclosed engine for supplying the power, affords the very 
highest economy and convenience. This arrangement gives 
positive control over the tension of belts, ensures the greatest 
rigidity, ease in adjustment, perfect alignment, and when it is 
desirable, an immediate change in the speed of the blower. The 
latter is a very desirable feature, especially in cupola work, 
because in hot weather it requires an increased volume of air to 
melt the same quantity of iron over that of cold weather. It 
will readily be seen that this arrangement possesses marked 
advantages over blowers with power by belt transmission, as 
they may be run whenever desired, and are independent of 
other sources of power. 
20 



306 



THE CUPOLA FURNACE. 



The design of engine, together with the workmanship and 
material employed, is identically the same as upon the regular 
Bufifalo Double Upright Enclosed Engine. This design of engine 
is peculiarly fitted for driving steel pressure or cupola blowers. 
In foundries or forge shops, much dust and dirt are present in 
the atmosphere, but the running parts of the engine are thor- 
oughly protected therefrom. As will be seen by reference to 
Fig. 64, this engine is furnished with a common oil chamber 

Fig. 64. 




BLOWER AND UPRIGHT ENGINE. 



on top of frame, from which oil tubes of different sizes, accord- 
ing to the function each is to perform, lead to every recip- 
rocating part. Continuous running is possible without the re- 
peated opening and closing of the door in engine. The engine, 
which is built in a variety of sizes for the different blowers, being 
especially designed and adapted for high rotative speed, possesses 
short stroke, and the reciprocating parts are perfectly balanced. 

BUFFALO ELECTRIC BLOWER BUILT IN " B " AND STEEL PRESSURE TYPES. 

The " B " Volume Blower, illustrated in Fig. 65 is built with 
electric motors of approved type as a part of the fan, and con- 
nected directly to the fan shaft. Electric fans afTord greater 



BLOWERS. 



307 



convenience even than direct attached engine fans. They are 
unrivaled in their adaptabiHty to all classes of work, and to all 
locations. To start and stop is simply a matter of moving a 
switch or pushing a button, according to the arrangement. No 
engines or belts are required, and they are always ready for 
immediate use. 

One special feature of their great convenience, to which par- 
ticular attention should be called, is the fact that the fans can 
be set up in any position without affecting the running of the 

Fig. 65. 




ELECTRIC BLOWER. 



motor. This so adapts the fans that they may be located to 
discharge or exhaust from any desired direction, which entails 
the least complication of pipe connections. The "B" volume 
type of blower and exhauster, when built as an electric fan, can 
readily be furnished in the different styles of discharges described 
for this design. 

All types of fan built by this house can be readily fitted and 
furnished with direct attached electric motors, though, in the 
case of very large steel plate fans, it is usually more desirable to 



308 THE CUPOLA FURNACE. 

employ an independent motor, conveniently located, and then 
belt to the fan. All the fans supplied are of standard high grade, 
but are somewhat especially designed to receive the motors. 
That the highest efficiency may be secured, electric motors of 
approved design and special construction are built for the pro- 
pulsion of the different varieties of fans. They are also capable 
of continuous use with only ordinary attention. For ventilating 
work, these fans may be employed in a multitude of positions 
where the introduction of an engine and boiler required to derive 
the power for driving other varieties of fans would be impossible. 
All that is required is a wire connection with a power circuit, 
and the fan is ready for immediate operation. Electric fans 
may be driven at a high speed, therefore they are of large 
capacity. The combination of electric motor and fan, with 
proper care and under ordinary conditions of use, is noiseless 
in operation and is the acme of convenience. 

The Bufifalo Steel Pressure Blower is frequently furnished 
with electric motors attached direct to the shaft. It is desirable, 
especially in the larger sizes, to arrange the combination of steel 
pressure blower and motor substantially as shown in Fig. 65, 
substituting the motor for the engine. By properly proportion- 
ing the pulleys on countershafts, any pressure required for ordi- 
nary duty can be given while the motor is making its regular 
speed. 

BUFFALO BLOWER FOR CUPOLA FURNACES IN IRON FOUNDRIES. 

In the following table are given two different speeds and 
pressures for each sized blower, and the quantity of iron that 
may be melted per hour with each. In all cases, we recom- 
mend using the lowest pressure of blast that will do a given 
work. Run up to the speed given for that pressure, and regu- 
late the quantity of air by the blast gate. The proportion of 
tuyerage should be at least one-ninth of the area of cupola in 
square inches, with not less than four tuyeres at equal distances 
around cupola, so as to equalize the blast throughout. With 
tuyeres one-twentieth of area of cupola, it will require double 



BLOWERS. 



309 



the power to melt the same quantity of iron, and the blast will 
not be so evenly distributed. Variations in temperature affect 
the working of cupolas very materially, Hot weather requires 
an increase in volume of air to melt same quantity of iron as in 
cold weather. 



Table of Speeds and Capacities as Applied to Cupolas. 







1) c 






.'. '-' 


"t; x) 






1 i-t 


>*; —3 






■33 •- 







cS CL, 

1 


ii 







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Oh . 


iS 


<— 





1-1 


P • 


d S 


rt m 

.^ 


^^1 


c . 


3 ^ . 




V §-| 


^ 


a 
•— 1 . 

CP 

in 


(=5 


a c 
1-1 

CL, 


1 w "3 

CI, 




1-4 w 
.-. '^ (IJ 

■^< a. 


Pi 




'^ ."tii K 


U b. >-, 


4 


4 


20 


8 


4732 


1545 


666 


9 


5030 


1647 


717 


5 


6 


25 


8 


4209 


2321 


773 


10 


4726 


2600 


867 


6 


8 


30 


8 . 


3660 


3093 


951 


10 


4108 


3671 


1067 


7 


14 


35 


8 


3244 


4218 


i486 


10 


3642 


4777 


1668 


8 


18 


40 


8 


2948 


5425 


2199 


10 


3310 


6082 


2469 


9 


26 


45 


10 


2785 


7818 


3203 


12 


3260 


8598 


3523 


10 


36 


55 


10 


2195 


1 1 295 


4938 


12 


2413 


12378 


5431 


II 


45 


65 


12 


1952 


16955 


7707 


14 


2116 


18357 


8358 


">^ 


55 


72 


12 


1647 


22607 


10276 


'4 


1797 


25176 


III44 


12 


75 


84 


12 


1647 


25836 


"744 


14 


1797 


28019 


12736 



smith's dixie fan blower. 
This blower is constructed with a view to deliver a large vol- 
ume of air under moderate pressure with the least possible ex- 
penditure of power. It is the nearest to noiseless in operation 
of any fan blower made, and is of the simplest and strongest 
construction, the latest design, and is the lightest running fan 
in the world. It has steel shafts, wheels and casing, and is 
thoroughly tested and fully warranted. The construction of the 
case or shell of this blower is entirely different from anything 
heretofore made, and owing to its adjustable hanger bracket and 
feet on all four sides, it is adapted for any possible location 
or position. The illustrations. Figs. 66 and 6y, show how the 
blower may be changed from bottom to top horizontal dis- 
charge, by simply turning the bearing brackets on the side of 
blower cases. It can also be changed to bottom or top vertical 



3IO 



THE CUPOLA FURNACE. 



discharge as well, in less than five minutes' time, by simply- 
loosening four bolts on either side of the blower case and turn- 
ing the bracket one-fourth round either way. Tighten up again 
and the blower is changed and ready for operation as you want 
it. This blower is adapted to cupola furnaces aud forges, and 
for all purposes where a strong blast of air is required, or a 
large volume of air such as is needed in the melting of iron in 
foundry cupolas, for which purpose a large number of these 




Bottom Honzunlal Discharge. 

smith's dixie fan blower. 



blowers are now in use. The proper arrangement of pipes in 
connecting a blower with a cupola is a matter of great import- 
ance, if the full volume of blast from the blower is to be de- 
livered to the cupola. The friction of air through long or 
crooked pipes, which are much too small for the distance the 
air is to be conducted, or the pipes having one or more short, 
abrupt angles between blower and cupola, is often the cause of 
much annoyance and dissatisfaction, and frequently blowers of 



BLOWERS. 



311 



all makes are condemned as worthless, when the piping alone 
is at fault. A blower delivering air two hundred and fifty feet 
from the blower through an eight-inch diameter of pipe, the 
area of which is the same as the combined area of the tuyeres 
in cupola, will not deliver over two-thirds the pressure at the 

Fig, 67. 



nn]!^ iljrr"!"; 




Top Horizontal Discharge. 

smith's dixie pan blower. 



cupola that there is at the blower. Under like conditions a 
twelve-inch diameter of pipe would deliver 15-16 of the pressure 
at the blower to the cupola. Built by the American Blower 
Co., Detroit, Michigan. 



FORCED BLAST PRESSURE BLOWERS. 
THE MACKENZIE BLOWER. 

In Fig. 68 is shown a section of the Mackenzie Positive or 
Pressure Blower, which is probably the first rotary positive 
blower introduced in this country, and is certainly the first one 



312 



THE CUPOLA FURNACE. 



to come into general use for foundry cupolas. This blower was 
designed by the late P. W. Mackenzie and introduced in con- 
nection with the Mackenzie cupola, and was a decided improve- 
ment upon the rotary fan blower then in common use. The 
blower, although an old one, is said by those who have used it 
to be a good one, and a large number are at the present time 
in use in foundries in various parts of the country. A descrip- 
tion and claims for the blower are furnished by its present 

Fig. 68. 




SECTION OF MACKENZIE BLOWER. 



manufacturers, Isbell Porter Co., 46 Bridge St., Newark, N. J., 
as follows : 

It is a well-known fact that a trustworthy blast, thoroughly 
penetrating the charge, is of the utmost importance in the 
economical working of a cupola, saving in many instances twenty 
to thirty per cent, of coal. The Mackenzie blower is a positive 
or pressure blower, that is, it delivers a definite quantity of air 
for each revolution, regardless of the condition of the cupola. 
This, of course, is essential to the proper melting of iron. It 



BLOWERS. 



313 



requires less speed, has the least possible friction of parts, and 
consequently uses less power than any other blower made. The 
late P. W. Mackenzie in experiments with blowers found that 
no positive blower required more than six-tenths of the power 
required for the best fan blowers, when the pressure exceeded 
four-tenths of a pound per square inch. 

This blower is practically noiseless in operation, and fts dura- 
bility is unequaled. 

We build eieht sizes : 



No. 

3 


Dia. of Shell. 


Capacity per 
100 revolutions. 


Size of Outlet 
Opening. 


Floor Space 
occupied. 


Price. 


22" 


1300 cu. ft. 


9%" X 13K" 


58" X 36" 




4 


32 


1800 " 


10 X i8}4 


71 X « 




5 


48 


3200 " 


I2}i X 191^ 


70 X54 




6 


" 


4500 " 


13 X25 


82 X " 




7 


(( 


5600 " 


X 36>2 


94 X « 




8 


60 


7500 " 


19)^ X 24 


96 X75 


1 


9 


« 


I 0000 " 


" X 26 


108 X " 




10 


(C 


1 2500 " 


X 2^% 


120 X " 



No. 3 will supply blast for No. i and No. 2 Mackenzie Cupola with 2 to 3 H. P. 
« 4 '< " No. 3 " " " 3 " 4 " 

" 5 " " No. 4 and No. 5 " " " 4 " 5 " 

« 6 " " No. 6 " No. 8 " " " 6 " 7 " 

It will melt faster and with less power in straight cupolas 
than any other blower in use. 

No. 3 will supply blast for Cupolas to 30" dia. with 3 to 3^^ H. P. 

" 4 " " " 30" " 36" " " 3>2 " S 

« 5 " « » 36 " 48 « "5 "7 

« 6 " " " 48 " 60 " "7 "8 



The construction and operation of the machine will be readily 
understood from the cut. The blades are attached to fan boxes, 
which revolve on a fixed center shaft. Motion is imparted to 
them by means of a cylinder to which are attached the driving 
pulleys. Half-rolls in the cylinder act as guides for the blades. 



314 THE CUPOLA FURNACE. 

allowing them to work smoothly in and out as the cylinder re- 
volves. At each revolution the entire space back of the cylinder 
between two blades is filled and emptied three times. 

DIRECTIONS FOR SE.TTING UP BLOWER. 

Set the machine upon a level and substantial foundation, in a 
room free from dust. The main pipe should be equal in 
capacity to the combined capacity of the tuyere pipes. 

For blowers Nos. 3 and 4, the diameter of main pipe should 
be thirteen to fifteen inches, and for Nos. 5 and 6, the diameter 
of main pipe should be from sixteen to eighteen inches ; all 
connections must be permanently air-tight, and all curves made 
easy. The blades should be oiled freely for a few days, then 
they will show plainly where oil should be used. The shaft 
upon which the fan boxes revolve is hollow, and the opening to 
the oil passage in shaft will be seen outside the hanger and on 
top of shaft. Fill the shaft with oil when the machine is started, 
and supply a small portion occasionally when running. Keep 
the passages open so that the oil will find its way readily to the 
bearings. Use good oil, give the machine proper care, and it 
will last for years without repairs. 

THE GREEN PATENTED POSITIVE PRESSURE BLOWER. 

This is a blower of a new design recently placed upon the 
market by the Wilbraham-Baker Blower Co., Philadelphia, Pa., 
to take the place of the Baker blower, for many years manu- 
factured by them. The new blower is said to be a great im- 
provement upon the Baker blower, which is one of the best in 
use for foundry cupolas. Claims for the Green blower are made 
by the manufacturers as follows : 

This blower is designed to occupy the minimum space, dis- 
place the largest volume for the space occupied, exhaust and 
deliver in a practically even volume, have the least weight com- 
bined with ample strength, be entirely void of complications, 
compHcated shapes, sliding parts or sliding motion, the least 
liability to get out of order, the least weight to revolve, be en- 



BLOWERS. 



315 



tirely free of internal friction in case of wear of the journals, and 
do the work with the minimum power. 

The working parts are two perfectly balanced impellers, each 
of which is a single strong casting, well ribbed inside and firmly 
fastened to a steel shaft of ample dimensions, extending the full 
length of blower, the shaft being flattened where it passes 
through the body of impeller. 

The journal bearings are bushed with phosphor bronze and 
are detachable from blower, being bolted and dowel pinned to 

Fig. 69. 




SECTIONAL VIEW. 



the head plate, easily removed and returned to their original 
central position. 

The blower is geared at both ends, the gearing being of 
ample proportions, cut in the most accurate manner, and en- 
closed in an oil-tight cover, free from dust and dirt, and con- 
tinuously in oil. The case of blower is well-proportioned, 
strongly ribbed and firmly bolted together. 

The head plates, in addition to being well-ribbed, are further 
strengthened by having the hoods or extensions, into which 
the circular ends of the impellers project, a part of head-plate 
casting. 



3i6 



THE CUPOLA FURNACE. 



The circular parts of casing and the pipe plates are also ribbed, 
and the pipe plates are fitted in between and bolted to the head 
plates and circular casing. 

The finished surfaces of the impellers are two circles, which 
roll together without friction, forming an even and continuous 
practical contact; the point of contact being always on the 
pitch line of the gears and traveling at the same speed at all 
points of the revolution. 

The gear wheels are keyed to the shafts close to ends of 
journal bearings, forming collars at each end of blower, prevent- 

FiG. 70. 




COMPLETE IMPELLER. 

A single casting with Steel Forged Shaft in position. Two such pieces compose the interior working 
parts of Blowers and Exhausters. 



ing the impellers from rubbing endwise against the interior 
sides of head plates. 

These provisions insure an entire absence of internal friction 
at all times, and are a positive preventive of possible accidents. 

The following Fig. (71) shows Standard Green Blower with 
discharge outlet on either side. Fig. 69 a sectional view, and 
Fig. 70 the complete impeller. 

The inlet and outlet flanges are tapped for tap or screw bolts 
and provided with loose flanges for attaching light sheet-iron 
pipe. 

Directions for setting up. — Set the blower perfectly level and 
solid. Brick or stone is best for a foundation ; timber is liable 
to rot and allow blower to get out of level. See that oil holes 



BLOWERS. 



317 



are clean before attaching oil cups, and set cups to feed prop- 
erly. Before attaching pipes see that nothing has fallen into 
the blower. Fasten a coarse wire screen on end of inlet pipe. 
Wipe the gear wheels and gear casing perfectly clean before 
attaching the casing, and cover the joint between parts of gear 
casing with red or white lead. Put a supply of good heavy oil 
inside the gear covers, say a pint in each small, and a quart in 
each large cover, and draw off this oil and replace with fresh oil 

Fig. 71. 




STANDARD GREEN BLOWER. 



about once each month. Use a good fluid oil on journals and 
gear-wheels. No lubricant required inside of blower. 

Efficiency of blower. — The blower is not guaranteed to ac- 
complish any given duty ; the blower simply furnishes the air 
at its discharge outlet ; the result obtained depending upon the 
disposition of the air after it leaves the blower. Tight iron 
pipes must be used so that all the air delivered by the blower 
will reach the desired point. For overground, galvanized iron 
pipes, riveted and soldered, are good, and for underground, cast 
iron is the best. Cast iron blast gates are recommended. Light 



3l8 THE CUPOLA FURNACE. 

wrought iron or brass gates are liable to leak and impair the 
efficiency of the blower. A blast gate having the gate pass en- 
tirely through the frame is the best. 

Power. — For estimating the approximate amount of power 
required to displace a given amount of air at a given pressure, 
it is customary to add 25 per cent, to the net result obtained by 
using the following rule. Rule. — Multiply the number of cubic 
feet delivered per minute by the pressure in ounces per square 
inch (at the blower) and the product by .003 ; divide the last 
amount by 1 1, 



1 



BLOWERS. 



319 



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320 THE CUPOLA FURNACE. 

SPEED OF FOUNDRY BLOWERS. 

No. I blower displaces 3 cubic feet per revolution. Suitable 
for cupola 24 to 28 inches diameter for melting: 

^ tons per hour 125 revolutions per minute. 

i^ " " 210 

iX " " 290 

No. 2 blower displaces S/4 cubic feet per revolution. Suit- 
able for cupola 24 to 34 inches diameter, for melting: 

1}^ tons per hour 115 revolutions per minute. 

2)4 " " 230 

3 " " 275 

No. 3 blower displaces 9 cubic feet per revolution. Suitable 
for cupola 28 to 40 inches diameter, for melting: 

2 tons per hour no revolutions per minute. 

3 " " 165 

4M " " 245 

No. 4 blower displaces 1 5 cubic feet per revolution. Suitable 
for cupola 32 to 45 inches diameter, for melting: 

3 tons per hour 100 revolutions per minute. 

5 " " ^70 

61^ " " 220 " " 

No. 4)4 blower (small No. 5), displaces 20 cubic feet per 
revolution. Suitable for cupola $6 to 50 inches diameter, for 
melting : 

4 tons per hour 100 revolutions per minute. 

6 " " 150 

9 " " 225 

No. 5 blower displaces 25 cubic feet per revolution. Suit- 
able for cupola 42 to 56 inches diameter, for melting: 

5 tons per hour 100 revolutions per minute. 

8 " •' 1 60 " " 

10 " " 200 " " 

No. sH blower (small No. 6), displaces 35 cubic feet. Suit- 
able for cupola 48 to 64 inches diameter, for melting: 



BLOWERS. 321 

8 tons per hour 115 revolutions per minute. 

10 " " 145 

14 " " 200 " " 

No. 6 blower displaces 42 cubic feet per revolution. Suit- 
able for cupola 50 to 70 inches diameter, for melting: 

9 tons per hour no revolutions per minute. 

12 " " 145 

15 " " 180 

No. 7 blower displaces 6'j cubic feet per revolution. Suit- 
able for cupola 66 to 78 inches diameter, or two cupolas 48 to 
56 inches diameter, for melting: 

14 tons per hour 105 revolutions per minute. 

18 " " 135 

20 " " 150 " " 

No. 8 blower displaces 112 cubic feet per revolution. Suit- 
able for cupola 74 to 92 inches diameter, or two cupolas 54 to 
66 inches diameter, for melting : 

20 tons per hour 90 revolutions per minute. 

25^ " ;' "5 " - 

30 " " 135 "/ 

No. 7^ blower displaces 85 cubic feet per revolution. 

No. 9 blower displaces 200 cubic feet per revolution. 

Speed. — For blowers running continuously at pressures of 
about two pounds per square inch, the following maximum speed 
is recommended : 

No. of blower .1 2 3 4 4>2 5 5>2 6 7 8 

Revolutions per minute 250 250 225 200 200 175 175 150 135 loo 

Displacement per rev. in cubic feet .. . 3 5^0 9 "5 20 25 35 42 67 112 

CONNERSVILLE CYCLOIDAL BLOWER. 

The Connersville Positive Pressure Blower, manufactured by 
the Connersville Blower Co., Connersville, Ind., is one of the 
latest designs of blower, and has only been manufactured for a 
few years. A description of it is taken from the excellent cir- 
cular which is well worth reading by those contemplating the 
purchase of pressure blowers, and is as follows : 
21 



322 



THE CUPOLA FURNACE. 



The cycloidal curves, their nature, peculiarities and possi- 
bihties, have always been an attractive study, not only to the 
theoretically inclined, but more particularly to those interested 
in the many important applications of these curves in practical 
mechanics. The especial value of combining the epi- and hypo- 
cycloids to form the contact surfaces of impellers for rotary 
blowers, gas exhausters and pumps has long been recognized, 
and many attempts have been made to utilize them in that con- 
nection, but in vain. While conceded to give the theoretically 
correct form to a revolver or impeller, it came to be regarded 
as impossible to produce such surfaces by machinery with sufifi- 



Fi( 




SECTIONAL VIEW OF CONNERSVILLE CYCLOIDAL BLOWER. 



cient accuracy to admit of their use in practice with any degree 
of satisfaction. It remained for us to demonstrate that it could 
be done, and in a highly successful manner as well. 

Fig. 72 is an illustration showing a cross section of our new 
cycloidal blower, and particularly of the revolvers or impellers, 
their form, relation to each other, and to the surrounding case. 
A glance only is required to discern the superiority of this 
method of construction over all others. 

The vital part of every machine of this class is the impeller, 
as on it depend economy of operation and efficiency in results. 



BLOWERS. 323 

That we have the ideal form for an operating part is self-evident. 
It will be noted that there are two impellers only, and each is 
planed on cycloidal lines with mathematical accuracy. Now, it 
is one of the well-known peculiarities of the epi-cycloidal and 
hypo-cycloidal curves, when worked together as in our machines, 
that there is a constantly progressive point of contact* between 
the impellers. As a result of this regular advance of the point 
of contact, the air is driven steadily forward, producing a smooth 
discharge that is conducive to the highest economy. 

The advantage of this arrangement over the use of arcs of 
circles to approximate contact curves is very great, as it is a 
well-demonstrated fact that circular arcs whose centers are not 
co-incident with the centers of revolution can not keep practical 
contact through an angle of more than four or five degrees. On 
the contrary, the contact does not progress continuously, but 
jumps from one point to another across intervening recesses as 
the impellers revolve, leaving pockets in which the air is alter- 
nately compressed and expanded, producing undesirable pulsa- 
tions in the blast, a waste of power, and necessitating two points 
of contact at one time in four positions in each revolution. 

Another advantage of the cycloidal form is that, at the point 
of contact, a convex surface is always opposed to a concave 
surface ; that is, the epi-cycloidal part of one impeller works 
with the hypo-cycloidal part of the opposite impeller. The con- 
sequence of this is to produce a /oii£- co7i^act or distance through 
which the driven air must travel to get back between the im- 
pellers, instead of the short contact that results when two con- 
vex surfaces oppose each other, as is the case in other machines 
of this character. 

Attention has previously been directed to the fact that the 

* Wherever the expression " point of contact " is used in this description, it must 
not be understood to mean that the impellers actually touch at such points, but that 
it is the point of nearest z.-pTpro2L.ch. In practice it has been found advisable to allow 
a very slight clearance rather than have the parts rub together, as thereby friction and 
wear are entirely eliminated, while on account of the "long contact" referred to, the 
leakage is insignificant. Our method of planing the impellers enables us to make the 
clearance very slight. 



324 THE CUPOLA FURNACE, 

point of contact between the impellers continuously progresses ; 
indeed, the path it describes is a circle. One result of this con- 
tinuously-progressive contact, as before mentioned, is a smooth, 
reliable blast. Another is, as has also been noted, the absence 
of any pockets or cavities in which air can be gathered, com- 
pressed and then discharged back toward the inlet side of the 
machine, thereby entailing a waste of power and shortening the 
life of the blower by subjecting the impellers, shaft and gears to 
a needless shock, strain and wear. Furthermore, the impellers 
can be in contact only at one point at the same instant — in no 
position is it possible for them to touch each other at two points 
at once ; hence, there are no shoulders to knock together when 
the speed is more than nominal. 

On account, also, of there being no popping due to the ex- 
pansion of air when released from the pockets in which it has 
been caught and compressed, and no pounding of the impellers 
together, that disagreeable din and vibration usually associated 
with machines of this class is eliminated, and our blowers run 
with practically no noise. This is a feature that will commend 
itself to parties having had experience with other pressure 
blowers. 

Another point contributing to the evenness and uniformity of 
the discharge is the fact that the extremities of the impellers 
are curved. Thus, as they sweep past the outlet, there is a 
gradual equalization of the pressure instead of a sudden shock, 
such as results from the passage of two sharp edges, which 
shocks are so detrimental to all working parts, as has been noted. 

From what has been stated, we scarcely need to add that the 
machine is positive in its action. All the air that enters the 
blower is inclosed by the impellers, forced forward and dis- 
charged through the outlet pipe. The leakage is insignificant, 
and there is no compressed air allowed to escape backward. 
Hence, all the power applied to the machine is used for the 
purpose intended — the maintenance of an even blast, and none 
of it is wasted on needless work. 

Furthermore, as the contact between the impellers and the 



BLOWERS. 



325 



surrounding case is perfect at all times, the amount of pressure 
that can be developed and sustained depends solely on the 
strength of the machine and the power applied. 

Each of the two impellers is cast in one piece and well ribbed 
on the inside to prevent changes in form under varying condi- 
tions. It is part of our shop practice to press the shaft into the 
impeller with a hydrostatic press, finish the journals to standard 
size, mount the impeller on a planer and pla7ic its entire surface 
accurately. By this means we secure perfect symmetry and ex- 
actness with respect to the journal on which it revolves, and, as 
a consequence, can produce a machine that will run more 



Fig. -]'. 




HORIZONTAL BLOWER. 



smoothly, and in either direction, at a higher speed and press- 
ure than it has been possible to attain heretofore. 

It will be observed that the cycloidal curves produce an im- 
peller with a broad waist. We have availed ourselves of this 
to use a high-grade steel shaft of about twice the sectional area 
of those found in competing machines. The advantages of this 
need not be enumerated. 

In Fig. 73 we illustrate the styles of blowers that are most 
largely sold, /. e., those pulley driven. It will be noticed that 
we use one pulley only. We can, however, when desired, put 
a pulley on each end, but because of the large shafts, wide-faced 
gears, and the fact that there is a bearing the entire distance from 
the gears to the impellers, it is seldom necessary. In any event, 
we do not recommend two belts very highly, as, owing to the 



326 



THE CUPOLA FURNACE. 



difference in the amount of stretch in the leather, it is usually 
the case that one transmits most of the power. Indeed, it 
sometimes occurs that they work against each other. 

NUMBERS, CAPACITIES, ETC., OF THE CYCLOIDAL BLOWERS. 



Number of Blower . 



Capacity in cubic feet per rev- 
olution 

Ordinary speed 

Diameter of pipe opening — . 



y^ 


% 


I 


2 


3 


4 
12% 


5 


6 


7 
67 


% 


ii.. 


3 


sVa 


8 


24M 


42 


400 


350 


300 


275 


250 


200 


175 


150 


125 


4 


b 


8 


10 


12 


14 


lb 


20 


24 



100 
100 

30 



By "ordinary speed" we mean what would be about an 
average of every-day duty. It must be understood, however, 
that the peculiar form of the impellers of our blowers, in con- 

FiG. 74. 




VERTICAL BLOWER AND ENGINE ON SAME BED-PLATE. 



nection with the other superior points in construction, to which 
we have called attention, permits of higher speeds than com- 
peting machines. 



BLOWERS. 



327 



The speed at which positive pressure blowers are run may be 
classed as "slow;" therefore, power can be taken direct from 
the main line of shafting or from a countershaft driven at the 
same rate. 

Fig. 74 shows a blower with an engine to furnish the required 
power, both on the same bed-plate. By such a combination all 
shafting, pulleys, gears and belts are dispensed with, as the 
crank shaft of the engine is coupled direct to a shaft of the 
blower, thereby effecting a very simple but most efficient driving 
arrangement. We recommend the installation of such a plant 
when the blower is to be located at a considerable distance from 
the line shaft, as it will be found more economical to pipe steam 
to the engine than to transmit power by shafting or cable. But 

Fig. 75. 




Blower and Electric Motor. 

even where power is convenient there are many good reasons 
why it will be found much more desirable to operate the blower 
with its own engine. For instance, it can be run independent 
of the other machinery, as necessity or convenience may often 
require, and also permits the speed of the blower to be varied, 
as there is a demand for an increased or diminished amount of 
blast, while otherwise this could not be accomplished without a 
change of pulleys. 



328 THE CUPOLA FURNACE. 

In nearly every town there is now a station for electric-light- 
ing purposes, and managers of it are finding that they can 
extend the earning capacity of their plants and increase their 
profits by renting power at a time when otherwise their ma- 
chinery would be practically idle. We have arranged to have 
our machines operated by electric motors when desired. In 
Fig. 75 will be found an illustration of a motor geared direct 
to a blower, both on the same bed plate. When preferred, 
however, the motor can be located a short distance away, and 
the power transmitted to the blower pulley by means of a belt. 
Foundries and other industries needing power only to run their 
blowers will find it exceedingly advantageous and economical to 
adopt this plan. Not only will there be a saving in first cost, 
but the operating expense will be much less. 

Furthermore, the motors can have suf^cient power to run the 
rattler and other light machines about the establishment. 

GARDEN CITY POSITIVE BLAST BLOWERS. 

In Fig. ^6 is shown the Garden City Positive Blast Blower 
manufactured by the Garden City Fan Co., Chicago, 111., many 
of which are in use in foundries, and for which claims are made 
as follows : 

The operation of our blower is not on the fan principle, in 
which pressure is obtained by a high velocity or speed, but 
when the air enters the case at the inlet and is closed in by the 
vanes of the blower, it is absolutely confined and must be forced 
forward until finally released at the outlet, where it must have 
escape or the blower stop if outlet is closed. There is posi- 
tively no chance for loss by backward escapement of air, after 
it once enters the inlet. 

In many respects our blower has points of superiority over 
any positive blower made, and we call your attention to the fol- 
lowing points : 

1st. It has no gears whatever. No internal parts that require 
attention, adjustment or lubrication. 

2d. It fs only two journal bearings that are external to the 
blower casing. They are self-oiling. Easy of adjustment. 



BLOWERS. 



329 



. 3d. Has no irregular internal surfaces that require contact 
to produce pressure, and add friction. 

4th, Operating parts are always in perfect balance, thus 
blower may be safely run at a higher speed than any positive 
blower made, giving a proportionate increase in efificiency and 
a smaller blower may be used. 

5th, A higher pressure can be be obtained than is possible 
with any other. 

Fig. 76. 




Garden City Positive Blast Blower. 

6th. The blowers are practically noiseless as compared with 
all other makes. 



ROOTS'S ROTARY POSITIVE PRESSURE BLOWER. 

The Roots Blower was designed by Mr. Roots, of Connersville, 
Ind., nearly forty years ago. It is said that it was originally 
designed for a turbine water wheel, but when the water was 
let in it was all blown out, and Mr. Roots at once decided it 
would make a better blower than a water wheel, and after con- 
siderable experimenting, perfected it as a blower. Whether 



330 



THE CUPOLA FURNACE. 



this story be true or not we cannot say, but the machine cer- 
tainly makes a good blower, and hundreds of them have been 
used to furnish blast for foundry cupolas. A number of marked 
improvements have from time to time been made in it since it 
was originally invented, and the impellers, which were originally 
made of wood placed upon iron shafts and covered with bee's 
wax or soap to make them air-tight, are now made entirely of 
iron and accurately fitted. The shape of the blower cases has 
also been to some extent changed, and they are now constructed 
vertical and horizontal, as shown in Figs. ^J and 78. They are 

Fig. 77. 




ROOTS'S \'TERTICAL PRESSURE BLOWER. 



also made with blower and engine on same bed-plate or with 
blower and electric power motors on same bed-plate. The fol- 
lowing claims are made for it by the manufacturers, P. H. & F. 
M. Roots Co., Connersville, Ind. : 

1. It is simpler than any other blower. 

2. It is the only positive rotary blower made with impellers 
constructed on correct principles. 

3. It is the best, because it has stood the test of years and is 
the result of long experience. 

4. In case of wear of the journals, the impellers will not come 
together and break, or consume unnecessary power, as is the 
case with competing machines. 



BLOWERS. 



331 



5. The principles upon which our blowers are constructed 
admit of more perfect mechanical proportions than any other. 

6. The only perfectly adjustable journal box for this type of 
machine is used. 

7. The gears are wide-faced and run constantly in oil. 

8. The gears and journals are thoroughly protected from dust 
and accident. 

9. Our machine blows and exhausts equally well and at the 
same time, and the motion may be reversed at any time. 

10. All the operating parts are accurately balanced. 




KOOrs's HORIZONTAL I'KESSURE BLOWER. 



The principles upon which our blower is constructed are so 
radically different from any competing machine that we are en- 
abled to adopt proportions that are mechanically perfect, and 
hence we can speed our machines much faster than any other, 
with a far greater degree of safety. We are not compelled to 
cut down the weight of our blower cases, as other manufacturers 
do, in order to bring the weight of the complete machine within 
reasonable bounds. The distribution of metal in the shafting, 
impellers, gears and cases of all our blowers is perfectly propor- 
tioned, and it is the only rotary positive blower made so con- 
structed. 



CHAPTER XXII. 

CUPOLAS AND CUPOLA PRACTICE UP TO DATE.* 

There are three kinds of furnaces employed in the melting 
of iron for foundry work. They are known as the pot furnace, 
reverberatory furnace and the cupola furnace. These fur- 
naces differ from each other in construction and principle of 
melting, and in the days of poor fuel the employment of the 
pot furnace or reverberatory furnace in the melting of iron for 
special work was necessary to the production of good castings. 
But, with the discovery of veins of coal more suitable for melt- 
ing and coking and the advancement made in the manufacture 
of coke, the amount of deterioration to iron by impurities in 
the fuel has been reduced to a minimum, and the furnace that 
will melt with the smallest per cent, of fuel has, as a foundry 
furnace, been almost universally adopted, and the fuel that melts 
iron most rapidly has almost entirely taken the place of those 
melting more slowly. Charcoal, the furnace fuel of years ago, 
is only used in foundries located in isolated districts where 
other fuel is not obtainable. The use of hard coal in melting 
is almost entirely restricted to the anthracite coal field, and 
coke has become the almost universal fuel for foundry work. 

In the pot furnace, one ton of coke is consumed in melting a 
ton of iron. (2240 lbs.) In the reverberatory furnace, from ten 
to twenty cwt. of coke is required to melt a ton of iron. In 
the cupola furnace, a ton of iron may be melted with one hun- 
dred and seventy- two (172) pounds of coke. It will thus be 
seen that the cupola melts iron with a smaller per cent, of fuel 
than either of the other furnaces. To melt iron in a cupola 

* Prepared for the first meeting of the American Association of Foundrymen, May 
13, 1896, at Philadelphia, Pa. 

( 332) 



CUPOLAS AND CUPOLA PRACTICE UP TO DATE. 333 

with the small amount of fuel stated, the cupola must be prop- 
erly constructed and managed, which is not always the case, 
and the consumption of fuel as a rule is much greater, but is 
still not so large as that required in either of the other furnaces. 
To reduce the amount of fuel required to the smallest possible 
figure, a cupola must be of a size that will admit of it being run 
to its fullest capacity in melting a heat. The tuyeres must be 
placed low to prevent wastage of fuel in the bed, and the charg- 
ing aperture must be placed high to utilize all the heat of the 
fuel in heating the stock and preparing it for melting before it 
enters the melting zone. 

The rule for charging a cupola is to place three pounds of 
iron upon the bed to each pound of fuel placed there, and ten 
pounds of iron upon the charges of fuel to each pound of fuel 
in the charge. This rule is not always accurately followed, but 
it is approximately so, and when the cupola is so large that the 
entire heat is melted upon the bed in one charge (according to 
this rule), only three pounds of iron are melted to the pound of 
fuel. When ten charges are melted in the same cupola, with 
the same bed, eight pounds of iron are melted to one of fuel ; 
and the greater the number of charges, the less the per cent, of 
fuel required in melting, and it is only by melting a large 
number of charges and keeping the cupola in blast for many 
hours, that the small per cent, of fuel stated as sufficient to melt 
a ton of iron, can be made to do the work. 

Foundrymen, as a rule, cannot have their cupolas in blast 
all day, and are compelled to use large cupolas to melt in a 
given time the amount of iron required for their work, while 
others prefer to melt their iron rapidly ; and it is a question for 
each foundryman to decide for himself, whether it is more 
economical to use a large cupola and save time, or a small one 
and save fuel. The height or distance tuyeres should be placed 
above the sand bottom is from two to six inches, but they are 
sometimes placed as high as six feet. The general height for 
heavy work is from eighteen inches to thirty-six inches. The 
placing of tuyeres at so great a height is productive of the 



334 'i'HE CUPOLA FURNACE. 

wastage of a large amount of fuel, for the function of the fuel 
placed below the tuyeres is to support the stock in the cupola, 
and it takes no other part in melting and is not consumed in 
melting the longest heats. Its temperature, when a cupola is 
in blast, is below that of the melting zone, and molten iron in 
its descent through the fuel to the bottom of the cupola is not 
superheated, but its temperature is reduced to such an extent 
that hot iron can only be tapped from a cupola with high 
tuyeres, when the melting is so rapid that the molten iron passes 
down through the fuel under the tuyeres in such a large volume 
and so rapidly, that it is not chilled in its descent. 

While the fuel placed under the tuyeres is not consumed in 
melting, it is heated to so high a degree and ground up to such 
an extent in the dump that it is rendered worthless as cupola 
fuel, and every pound of unnecessary fuel placed in a cupola, 
by using high tuyeres, is a wastage of it. 

It is claimed by many foundrymen that it is necessary to have 
tuyeres placed high to collect and keep iron hot for a large 
casting. This is one of the fallacies handed down to us by our 
foundry forefathers, for iron can be drawn from a cupola with 
low tuyeres so much hotter, that it can be kept hotter in a ladle 
for any given length of time when properly taken care of than 
it can be kept in a cupola with high tuyeres. In all cases, 
tuyeres should only be placed at a sufificient height above the 
sand bottom to admit of molten irons being mixed for hand-ladle 
work, and to give sufificient time between taps for the removiag 
and replacing of large ladles for heavy work. 

Low charging doors are another legacy from our ancestors, 
and in their day the volume of heat escaping from low cupolas 
was so great that many attempts were made to utilze this waste 
for heating the blast, and supplying cupolas with a hot blast. 
Other attempts were made to divert the heat into side flues or 
chambers, for heating the iron prior to charging; but this 
feature of the old cupolas has given way more rapidly to modern 
ideas than the high tuyere, and cupolas in which charging doors 
were formerly placed six to eight feet above the bottom, now 



CUPOLAS AND CUPOLA PRACTICE UP TO DATE. 335 

have them placed ten to fifteen feet and even higher; and all 
the heat that escaped from the low cupola is now utilized in 
heating stock in the cupola prior to melting. 

The highest cupolas in use in this country at the present 
time are those of the Carnegie Steel Works, Homestead, Pa. 
The charging apertures in these cupolas are placed thirty feet 
above the iron bottom, and the heat to so great an extent, is 
utilized in heating stock prior to melting, that it has not been 
found necessary to line the iron stacks, as not sufficient heat 
to heat them escapes from the cupolas even when the stock is 
low. 

A cupola to do economical melting must not only be prop- 
erly constructed, but properly managed. In every cupola there 
is a melting zone or belt in which iron is melted. Below or 
above this zone iron cannot be melted, but it may be on the 
lower and upper edge of the zone, and in either case a dull iron 
is the result. The exact location of the melting zone is deter- 
mined by the volume of blast. A large volume places the zone 
a few inches higher and a small one brings it a few inches lower. 
For this reason, cupolas of exactly the same construction fre- 
quently have higher or lower melting zones and require a 
greater or less amount of fuel for a bed. The size and arrange- 
ment of tuyeres often increase or diminish the depth of the 
melting zone, and to obtain the best results in melting the 
location and depth of the melting zone must be learned, and 
the weight of the bed and charges varied to suit the zone. 

The top of the melting zone may readily be determined by 
the length of time required to melt iron after the blast is put 
on. If iron comes down in five or ten minutes, the iron on the 
bed has been placed within the melting zone. If it does not 
come down for twenty or thirty minutes after the blast is on, 
the iron has been placed above the melting zone by too great 
a quantity of fuel in the bed, and the delay in melting is due to 
the time required in removing the surplus fuel by burning it 
away. If iron comes down in five or ten minutes and is dull, 
and at least three pounds of iron cannot be melted to one of fuel 



336 THE CUPOLA FURNACE. 

in the bed before iron comes dull, the bed is too low and the 
iron, when melting began, was not placed at the top of the 
melting zone. By noticing the melting in this way, the height 
of the zone can readily be found and the exact amount of fuel 
required for a bed determined. The depth of the zone can be 
found by increasing the weight of the first charge of iron until 
the latter part of the charge comes dull, which indicates that 
it is being melted too low in the zone, and the weight of the 
charge should be decreased. 

The quantity of fuel required for a bed and the amount of 
iron that can be melted upon it having been determined, tests 
are then made to ascertain the amount of fuel required in the 
charges and the amount of iron that can be melted upon each 
charge. The amount of fuel required in each charge is the 
amount that will restore the bed to the same height above the 
tuyeres at which it was before melting the first charge. This 
is found by increasing or decreasing the fuel until the melting 
becomes continuous and there is no variation in the tempera- 
ture of the iron at the end of each charge. A stoppage or 
slacking in the melting denotes that the charge of fuel is too 
heavy and the iron upon it is placed above the melting zone. 
Dull iron at the latter end of a charge indicates that the charge 
of iron is too heavy, and so on throughout the heat. 

By carefully noticing the melting in every part of the heat, 
the peculiarities of any cupola in melting may readily be learned, 
and a large amount of fuel saved. 

These rules for melting are not always followed, and in nine 
cupolas out of ten too great an amount of fuel is consumed. It 
is a common practice of melters, if not closely watched, to 
gradually increase the fuel in charging, and when iron comes 
dull they attribute it to poor fuel or not enough of it, and in 
either case more fuel is the remedy, and as a rule dull iron and 
slow melting are the result. Fast mehing cannot be done, or 
hot iron melted, with too large a quantity of fuel in a cupola. 
The reason for this is, that with an excess of fuel, the iron is 
placed above the melting zone and the extra fuel must be con- 



CUPOLAS AND CUPOLA PRACTICE UP TO DATE. 337 

sumed before the iron can come within the zone, and the result 
is slow and irregular melting. 

Iron held just above the zone for any length of time is heated 
to so great an extent that when it enters the melting zone it 
melts rapidly in one mass, and its descent through the melting 
zone in a molten state is so rapid that it is not superheated in 
passing through the zone, and drops through to the bottom of 
the cupola a dull iron. Slow melting is always the result of an 
excess of fuel, and dull iron is more often the result of an ex- 
cess than of a deficiency of fuel. 

The per cent, of fuel required in melting when a cupola is 
properly constructed and managed depends entirely upon the 
length of time required to melt a heat. In short heats of two 
to three hours eight pounds of iron to one of coke may be 
melted, and by careful management good hot iron for light work 
be made. The melting generally done in heats of this length 
is between six and seven to one. In long heats thirteen to 
one has been melted, but this ratio is seldom for any great 
length of time maintained ; for the quality of fuel varies, and 
foundrymen prefer to use a little extra fuel rather than take 
chances of a bad heat, and in heats requiring from one to six 
days to melt the average melting is about ten to one. 

It should be the aim of every foundryman to reduce his melt- 
ing to a system. He should first see that the cupola is properly 
constructed, and then study its working in the manner described. 
When this has been learned, a slate should be made out and 
given to the melter, indicating the exact amount of fuel to be 
placed in the bed and charges, and the exact amount of iron in 
each charge, as well as the amount of each brand of iron or 
scrap in it. 

As the lining burns out and the cupola diameter increases, the 
weight of charges of fuel and iron should be increased to cor- 
respond with the enlargement of the cupola. An accurate 
cupola record should be kept and the amount of fuel consumed 
in melting compared with each carload or lot of coke, to prove 
that no extra fuel is being used by the melter. When such an 
22 



338 THE CUPOLA FURNACE. 

account is accurately kept by every foundryman, much less fuel 
will actually be consumed in melting than at the present day, 
and at the same time claims of melting ten to one in short heats 
and fifteen or twenty to one in long heats will no longer be 
heard. 



CHAPTER XXIII. 

CUPOLA SCRAPS. 
BRIEF PARAGRAPHS ILLUSTRATING IMPORTANT PRINCIPLES. 

Make a heat, take a heat, make a cast, make a mould, riui a 
melt, casting, moulding, are all terms used in different sections 
of the country to indicate the melting of iron in a cupola for 
foundry work. 

When iron runs dull from a cupola, draw all the melted iron 
off at once and prevent the newly melted iron being chilled by 
dropping into dull iron in the bottom of the cupola. 

When slag flows from a tap-hole with a stream of iron, when 
the iron is not drawn off too close, it is due to too much pitch 
in the sand bottom. 

The formation of slag in a spout is due to poor material used 
in making up the spout. 

Some foundrymen do not seem to know what hot iron is, for 
they call all kinds of B. S. hot iron, if it will run out of the ladle. 

The cutting out of the spout lining in holes by the stream of 
molten iron is due to a deficiency of cohesive properties in the 
lining material when heated to a high temperature. 

When a tap-hole closes up with slag and cannot be kept 
open, the slag is generally produced by the melting of the ma- 
terial used in making up the front and tap-hole. Slag made in 
the cupola flows from the tap-hole without clogging it. 

A little sand or clay-wash added to the front and spout 
material will generally correct the deficiencies in the material 
and save the melter a great deal of trouble with his spout and 
tap-hole. 

In a spout with a broad flat bottom the stream takes a differ- 
ent course at every tap, the spout soon becomes clogged with 

(339) 



340 THE CUPOLA FURNACE. 

cinder and iron, the molten iron flows in all directions, and the 
spout looks like a small frog pond with patches of scum. Make 
the bottom of the spout narrow and concentrate the stream in 
the center. 

If the sand bottom does not drop readily when the doors are 
dropped, there is too much clay in the bottom material. Mix 
a little sand and cinder riddled from the dump with it, or some 
well-burnt moulding sand. 

A hard rammed bottom causes iron to boil in a cupola the 
same as in a hard rammed mould, and is frequently the cause of 
a bottom cutting through. A bottom should be rammed no 
harder than a mould. 

Wet sand in a bottom not only causes iron to boil, but 
hardens it. Bottom sand should be no wetter than moulding 
sand when tempered for moulding. 

Exclusively new sand should not be employed in making a 
bottom. The old bottom with a few shovels of sand riddled 
from the gangways makes the best bottom material. 

Often, a melter " don't know " why the cupola is working 
badly, because, if he knew, he would be discharged at once for 
carelessness. 

A bad light-up makes a bad heat. The bed must be burned 
evenly or it will not melt evenly. 

If the wood is not all burned up before iron is charged, the 
wood smokes and the melter can not see where to place the fuel 
and iron when charging. Never use green wood for lighting up. 
When green wood is used for lighting up, the bed is frequently 
burned too much before the wood is burned out, and the cupola 
is free of smoke. 

Don't burn up the bed before charging the iron. When the 
fuel is well on fire at the tuyeres and the smoke is all burned 
ofif, put in the front, close the tuyeres and charge the iron at once. 

If anything happens to delay putting on the blast after the 
fire is lighted, do not let that delay charging the iron, for the 
bed will last longer with the iron on it than it will with it ofif. 
Charge the iron as soon as the bed is ready for charging ; close 



CUPOLA SCRAPS. 341 

the front and tuyeres and open the charging door to stop the 
draught, and the cupola may be left to stand for hours and as 
good a heat be melted as if no delay had occurred. 

A melter who burns up his tapping bars so that two have to 
be welded together to make one almost every heat, don't know 
how to put in a front or make his bod stufif. 

The amount of fuel wasted every year in the United States 
by the use of high tuyeres in cupolas is sufficient to make a 
man very rich. 

A new cupola always effects a great saving in fuel, but it is 
often hard to find the fuel (saved) at the end of the year. A 
little more practical knowledge in managing the old cupola will 
often enable the foundryman to find the fuel saved and price of 
the new cupola besides. 

Never run a fan in its own wind merely to show a high press- 
ure on the air-gauge. 

The volume of blast supplied to a cupola should be regulated 
by the speed of the blower and not by the size of tuyeres. 

That old " no blast " story of the melter has had its day among 
practical foundrymen. 

The air-gauges in use at the present time for showing the 
pressure of blast on a cupola are an excellent thing to prevent 
a poor melter from claiming he has no blast and blaming a bad 
heat on the engineer, for the gauge always shows a higher 
pressure of blast when the cupola is bunged up from poor man- 
agement. 

High tuyeres in a cupola are an inheritance left us by our 
forefathers in the foundry business, of which we have never 
got rid. 

The only general improvement made in tuyeres in the past 
fifty years has been in increasing them to a size that will admit 
the blast freely to a cupola. The only local improvement has 
been in placing them lower. 

Molten iron should be handled in a ladle and not held in a 
cupola. Nothing is gained by holding iron in a cupola to keep 
it hot. 



342 THE CUPOLA FURNACE. 

" I will let that go for to-day, and to-morrow I will take more 
time and fix it right," is a remark frequently made by melters. 
That kind of work is often the cause of a very bad heat. 

Pig-iron melts from the ends, and the shorter it is broken the 
quicker it will melt. 

Tin-plate scrap may be melted in a cupola the same as cast 
iron. It throws off sparks from the tap hole and spout similar 
to hard cast iron. 

The fins on castings made from tin-plate scrap must be 
knocked off with the rammer, for the castings are too hard and 
brittle to be chipped or filed. 

The loss of metal in melting tin-plate scrap in a cupola is not 
so great as in melting iron when melted with a light blast, but 
the loss may be as great as 25 per cent, when melted with a 
very strong blast. 

The cost of melting iron in a cupola is about two dollars 
per ton. 

The cost of melting tin-plate scrap in a cupola is from three 
to four dollars per ton. 

Galvanized sheet iron scrap, when melted with tin-plate 
scrap, reduces the temperature of the molten metal to such an 
extent that it cannot be run into moulds. 

Anthracite coal picked from the dump of a cupola will not 
burn alone in a stove or core oven furnace, and it is very doubt- 
ful if it produces any heat when burned with other coal in a 
cupola. 

Lead is too heavy and penetrating when in a fluid state to 
be retained in a cupola after it has melted. The ladle should 
be warmed and the tap hole left open when melting this metal 
in a cupola. 

The best lining material for a cupola in which tin-plate scrap 
is melted is a native mica soap-stone. 

The sparks that fly from a stream of hard iron at the tap 
hole and spout are the oxide of iron. They are short-lived and 
burn the flesh or clothing very little. 

The sparks from a wet tap-hole or spout are molten iron, and 
burn wherever they strike. 



CUPOLA SCRAPS. 343 

We have probably chipped out, daubed up and melted iron 
in a greater number of cupolas and in more different styles of 
cupola than any melter in the United States, and in heats that 
require from two or three hours to melt, and we have found 
that 8 pounds of iron to i pound of best coke ; 7 pounds of iron 
to I pound of best anthracite coal ; 6 pounds of iron to i pound 
of hard wood charcoal ; 4 pounds of iron to i pound of gas-house 
coke, is very good melting. We have done better than this in 
test heats, but do not consider it practicable to melt iron for 
general foundry work with less fuel than stated above. 

The best practical results for melting for general foundry 
work are obtained from 6^ to 7 pounds of iron to i pound of 
coke ; 5 to 6 pounds of iron to i pound of hard coal ; 4 to 5 
pounds of iron to i pound of hard wood charcoal ; 3 lbs. of 
iron to i pound of gas-house coke. 

A less per cent, of fuel is required in long heats than in short 
ones, for, as a rule, three to one is charged on the bed and ten 
to one on the charges, and the greater the number of charges 
melted, the less the per cent, of fuel consumed. 

Ten pounds of iron to one of coke are melted at the Home- 
stead Steel Works, in cupolas that are kept in blast night and 
day for six days. 

Less fuel is generally required to melt iron in the foundry 
office than is required to melt it in a cupola. 

Use a light blast when melting with charcoal or gas-house 
coke. 

If you go into the foundry when the heat is being melted and 
find the tap-hole almost closed, the spout all bunged up and 
the melter picking at the spout with a tap bar and running a 
rod into the tap-hole a yard or so in his efforts to get the iron 
out, and remark to him: "You are having some trouble with 
your cupola to-day," he will say : " Yes, we have some very 
bad coke to-day, sir; that last car is poor truck;" or, " We are 
melting some dirty pig or scrap to-day, sir." He never thinks : 
"We have a very poor melter to-day, sir." 

At the first meeting of the American Association of Foundry- 



344 THE CUPOLA FURNACE. 

men, held in Philadelphia, May 12, 13, 14, 1896, one of the 
delegates was Mr. C. A. Treat, a good-sized practical foundry- 
man weighing over 300 pounds, and representing the C. A. 
Treat Mfg. Co., Hannibal, Mo. After the meeting had efTected 
a permanent organization, transacted all its business and was 
about to adjourn, Mr. Treat arose and in his quiet way re- 
marked : " Gentlemen : Since we have have formed an organ- 
ization of foundrymen for our mutual benefit, don't you think 
it would be a good idea for foundrymen to stop lying to each 
other?" The burst of laughter that followed this remark was 
loud and long. It would be a great relief to many foundrymen 
if some foundrymen would take the hint and stop lying about 
the large amount of iron melted with a small amount of fuel, 
fast melting, etc. 

A few years ago, a foundryman who was about to publish a 
work on foundry practice, being desirous to obtain some reli- 
able data on cupola practice, had several hundred blanks printed 
and sent to foundrymen in different parts of the country, with 
the request that they fill in the amount of fuel placed in the bed 
and charges, the amount of iron placed on bed and charges, 
diameter of cupola, height of tuyeres, etc. He was surprised 
at the reports received in reply. Many of them showed that 
the men who filled in the blanks either knew nothing at all 
about a cupola, or, knowing the report was to be published, 
were desirous of making an excellent showing of cupola work in 
their foundries, and in many of the reports the cupola was filled 
with stock in such a way that not a pound of iron could have 
been melted in a cupola charged as indicated in the formula. 
In some cases, the amount of fuel placed in the bed was not 
sufficient to fill to the tuyeres a cupola of the diameter given ; 
in others, the fuel placed in the charges was not sufficient to 
cover the iron and separate the charges ; and it was only after 
pointing out these mistakes and returning the reports for cor- 
rection, in some cases two or three times, that they were put in 
any kind of shape for publication. 

Some fifteen years ago, when we took a more active part in 



CUPOLA SCRAPS. 345 

melting than at the present time, and occasionally published an 
account of heats melted, we were repeatedly criticised in print 
by some would-be melters, who were melting anywhere from 
ten to twenty to one, for using too large a quantity of fuel, and 
some times were invited to come to their foundries and get a 
few points on melting before publishing another work on the 
subject. We have never learned of any of our critics on the 
fuel question becoming prominent in foundry matters or rich in 
the foundry business, and presume they have all saved their 
employers such a large amount of fuel in melting that they have 
been placed upon the retired list with half pay. 

The heats published at that time were the best that could 
be melted in the cupolas described, and the amount of fuel con- 
sumed was generally about seven to one with hard coal and 
eight to one with best Connellsville coke. The foundrymen 
who at the present time melt heats of the same size in cupolas 
of the same diameter, with a less per cent, of fuel, are like an- 
gels' visits, few and far between. 



NOTE. 



I'AXSON-COLLIAU CUPOLA. 

On page 193 are shown illustrations of the Paxson-CoUiau Cupola as built by 
J. W. Paxson Co., Philadelphia, and on page 194 we have stated that this is a hot blast 
type similar to that made by Victor CoUiau. 

We desire to correct the above to the extent that the Paxson-Colliau Cupola is not 
claimed to be of the Hot Blast type, and while it has two zones of melting as has the 
Colliau, there have been made many changes in its construction, bringing it up to date. 

The new Paxson-Colliau has a low safety tuyere which discharges any overflow into 
a cornucopia-shaped trap fitted with a soft metal plug, which is easily melted, and 
should any hot iron or slag strike it, it is discharged outside through the bottom 
plate, as shown by Fig. 44, page 193. 

This cupola is also fitted with a fine Screen Charging Door, as shown by Fig. 43, 
same page, requiring no lining, and is claimed to be more acceptable than the old 
solid cast iron doors, as it does not warp or crack. It may be fitted with a new 
arrangement to hold up the bottom doors, instead of the old prop, when a small car 



346 THE CUPOLA FURNACE. 

or truck on wheels or rake can be placed under the cupola to receive the hot drop 
and carry it into the foundry if desired, which is often done during cold weather to 
keep the shop warm, or to keep it out of the way, perhaps in the yard, where it can 
be cooled off by water, and gotten ready for the cinder mills. The cupola then will 
cool ofif quickly, allowing any repairs to be made or patching up the burned-out por- 
tions. 

A new device of a Spark Arrester is also placed over the Paxson-CoUiau Cupola, 
which confines the sparks and dirt to a small area. The lower tuyeres are rectangular 
and flared, and the upper ones are oval; they are staggered so that there is very little 
dead plate; the blast reaches every part where it is wanted, being distributed evenly. 
Therefore the lining is not affected by the action of the blast to the extent that would 
be expected where upper and lower tuyeres are used and two zones of melting are at 
work. 

While speaking of this it may be mentioned that we have seen the naked hand 
placed in the Paxson-Colliau furnace at the charging door during the greater part of 
the heat without injury. Did you ever try this in an ordinary cupola while running 
a heat? The hand will be pulled back very quickly. This proves the fact that there 
is enough oxygen admitted through the small upper tuyeres to make a more perfect 
combustion of the fuel where it is wanted, both below and above the tuyeres. 

A new tnerctiry blast gauge is supplied with each cupola. It is made of iron and 
japanned, except the brass scale-plate and glass tube. This is the neatest looking and 
most common-sense gauge we have yet seen. A further description of this cupola 
may be had from the builders, J. W. Paxson Co., Philadelphia, Pa. E. K. 



INDEX. 



ABENDROTH BROS. , Port Chester, 
N. Y., cupola re- 
port of. 214, 215 
Port Chester, N.Y., 
cupola with three 
rows of tuyeres 
i:.sed by, 43 
Port Chester, N.Y., 
large cupola in 
the foundry of, 
198-202, 298 
Accounts, cupola, 214-221 

manner of keeping, 214 
Adjustable tuyeres, 45, 46 
Air, admi.ssion of, to the cupola, 30 
-chamber, 14-16 

admission of blast to, 15, 

16 
area of, 5, 6 

belt, connecting blast pipes 
with tuyeres direct from 
a, 286-290 
construction of, 14, 15 
location of 14 
openings in the, 16 
perfect manner of connect- 
ing the main pipe with 
an, 290 
round or over-head, objec- 
tion to, 15 
chambers, air capacity of, 15 
best, 15 

perfect connection of, 286 
cubic feet of, required to melt a 

ton of iron, 293, 294 
friction of, in pipes, 281 , 282 
gauges, 292, 341 
means of supplying, to a cupola, 

294 
required for the combustion of 

fuel, 295, 296 
restriction to the passage of, 

through the cupola, 294 
rule for estimating the amount of 
power required to displace a 
given amount of, at a given 
pressure, 318 



American Blower Co., Detroit, Mich., 

Smith's Dixie fan blower built by 

the, 3(j9-311 
Angle iron or brackets for the support 

of the lining of a cupola, 23, 24 
Anthracite coal, amount of, required 

to melt iron, 90 

BAD melting, cause of, 247 
caused by wood and coal, 

250, 251 
examples of, 233-253 
Banking a cupola, 277-279 
Bar for cutting away the bod, 93 
Bars, tapping, 92, 93 
Baskets for measuring fuel, 230 

increase in size of, 212 
Bed, the, 77-79 

best depth of, 125 

burned too much, poor melting 

due to, 249, 250 
burning the, 340 

up the, for warming the cu- 
pola, 77 
depth of fuel in the, 78 
effect of too large a quantity of 

fuel in a, 128 
fuel required for a, 79 
leveling the top of the, 82 
quantity of fuel for a, 336 
raising or lowering a, 78, 79 
uneven burning of the, 253 

up of the, effect of, 77 
Belt air chamber, connecting blast 
pipe with tuyeres direct from a, 286- 
290 
Bessemer steel works, location of tuy- 
eres in cupolas used in, 53 
Blakeney cupola, 204, 205 

tuyere, 35, 36 
Blast, 85, 86 

admission of, to the air-chamber, 

15, 16 
air-chamber for supplying the 

tuyeres with, 14 
arrangement for supplying, 266 
cause of apparent deficiency of, 91 



(347) 



348 



INDEX. 



Blast, direct delivery of, to tuyeres, 
284 
furnace, definition of a, 136 
fuel required in, 1 
use of lime-stone in the, 135, 
13() 
gate, advantage of the, 290, 291 
gates, 29U-292 
gauges, 292-294 
heating the, 274 
in melting, 294-299 
indications of, when first put on, 

85 
length of time the, can be taken 

off a cupola, 27G. 277 
machines for supplying, 294 
passage of, through heated fuel, 

127 
pipe, preventing gas from the 
cupola from passing into the, 85 
pipes, 279-2S1 

blast gates, 276-299 
connection of, with cupolas, 

2S1 
diameter of, 281-290 
explosion in, blast gauges, 

blast in melting, 276, 277 
explosions in, 292 
galvanized iron, 280, 281 
long, poor melting caused by, 

290 
materials for, 280 
poor arrangement of, 286-288 
table of diameter and area 

of, 285 
table showing the necessary 
increase in diameter for the 
different lengths of, 283 
underground, 279, 280 
very best way of connecting, 

with tuyeres, 288-290 
positive and non-positive, 

294, 295 
putting on the, 85 
taking off the, during a heat, 

276-299 
time for charging the iron 
before putting on the, 86, 87 
Blower and electric motor, 327 

Buffalo steel pressure, 301-309 
connection of tuyeres with, 5 
Connersville cycloidal, 321-328 
directions for setting up, 314, 

316,317 
efficiency of, 317, 318 
foundation for, 300 
Garden City po.sitive blast, 328, 
329 



Blower, Green patented positive pres- 
sure, 314-321 
horizontal, 325 
Mackenzie, 311-314 
obtaining the best results from a, 

303 
on adjustablebed,and on bed com- 
bined with 
c o untershaftj 
303-305 
combined with 
double up- 
right engine^ 
305, 306 
placed near cupola, 290 
placing, 300, 301 
prevention of the destruction of 

a, 300, 301 
Roots "s rotary positive pressure, 

329-331 
Smith's Dixie fan, 309-311 
vertical, and engine on same bed, 
326 
Blowers, 300-331 

cycloidal, numbers, capacities, 

etc., of, 326 
forced blast pressure, 311-331 
foundry, speed of, 320, 321 
standard foundry, driven by pul- 
ley, table of dimensions of, in 
inches, 319 
table of speed and capacities of, 
as applied to cupolas, 309 
Blue clays for spout lining, 68 
Bod bar for cutting away the, 93 
definition of, 94 
good, qualities of a, 95 
for small cupolas, 95 
horse manure as an essential of 

a good, 95 
material, 94, 95 

working the, 96 
mixture for, 95 
mode of making the, 96 
size and shape of, 9(5 
sticks, 9:!, 94 

wet, explosion of iron caused by 
a, 257 
Boiling, cleaning iron by, 147, 148 
Bolton vSteel and Iron Co., England, 

use of Ireland's cupola in, 159 
Bosh, taper from the, to the lining, 109 
Boshing of cupola, 14 
Bottom door, 4 

1)olts and latches of, 4 
Bottom doors. 11, 12 

devices for raising the, 
133,134 



INDEX. 



349 



Bottom doors, way for reducing size 

and weight of, 1'5 
Bottom, exclusively new sand in a, 340 
hard rammed, 340 
high pitch of, 66 
hollow, 66 

of cupola, height of, 3, 11 
pitch or slope of, 65, 66 
plate, 4 

plates, shape of, 2() 
sand, introduction of, into the 
cupola, 63, 64 
preparation of, 63 
renewal of, 64 
re-use of, 63 

too wet or too hard, conse- 
quence of, 65 
tuyere, 46-49 
uneven settling and breaking of, 

10 
wet sand in a, 340 
Brackets, arrangement of, :23-26 
Brick, curved, for lining, 22 
for casing, 111 
split, 112 
Bridging, cause of, 9fl, 100 
Buffalo blower for cupola furnaces in 
iron foundries, 30<S, 309 
electric blower built in "B " and 

steel pressure types, 306-308 
Forge Co., Buffalo, N. Y., bank- 
ing a cupola at 
the, 277-279 
table of diameter 
of blast pipes 
prepared by 
the, 281-283 
School Furniture Co, Buffalo, 

N. Y., cupola of the, 54 
steel pressure blower. 301-309 
Byrani & Co. Iron Works, Detroit, 
Mich., cupola report of, 214-216 

CANNON, melting of, 224 
Carbon, effect of, upon cast iron, 
145 
removal of, from iron, 145 
Carnegie Steel Works, Homestead, 

Pa., cupolas in the, 275, 298, 335 
Cars for removing the dump, 100 
•Casing, 12-14 

brick for the. 111 

cupola, construction of, 12 

lining of, 6, 7 

preventing the, from rusting off 

at the bottom, 25 
refractory material for lining, 21, 
22 



Casing, stack, 2, 5 

construction of, 12 
strain upon the, 12 
thickness of, 12 

lining, to protect the, 
111 
wrought iron, 5 
Casings, 4, 5 
Cast, make a, 339 

iron, quantity of, that can be 
melted in a cupola, 224 
size and weight of a piece of, 
that can be melted in a cu- 
pola, 224 
Casting, 339 
Castings, fins on, 342 

report of, 219 
Center blast cupola, Ireland's. 159-161 
tuyeres, experiments with, 
298, 299 
Chain blast. 294 

Charcoal, experiments in softening 
iron with, 130-132 
use of, as fuel, 332 
Charge, fuel required in each, 336 
Charges, division of fuel and iron into, 
212 
effect of too large a quantity of 

fuel in the, 128 
for experimental heats, 126, 127 

most even melting, 127 
placing the, 82-84 
table of. 20*' 
Charging, 80-82 

bad, poor melting due to, 84 
cupola slate for, and cupola re- 
port, 220 
cupolas, different ways of, 113 
door, 6, 14 

distance of the floor of the 

scaffold below the, 26 
location of, 13 
wear of lining at the, 1 10 
doors, low, 334, 335 
flux, 84, 85 
proper way of, 84 
rule for, 333 
time for, 132, 133 
Chenney tuyere, 41 
Chill mould, explosion of iron in a, 

259 
Chipping out, 101-103 

tools for, 255 
Cincinnati, O., poor melting in a cu- 
pola at, 251--53 
Cinder, brittle, making a, 136 
chipping off, 106 
tendency of, in a cupola, 136, 137 



350 



INDEX. 



Clam shells, 142 

Clay, amount of sand in, for daubing, 
104 
and sharp sand, mixtures of, 62 
effect of too much, in lining, 68 
blue, for daubing, 104 
fire, for daubing, 104 

soaking of, 104 
sands, 62 
wash, 63 

yellow, for daubing, 104 
Clays for spout lining, 68 
Coal and wood, bad melting caused 
by, 250, 251 
anthracite, amount of, required 

to melt iron, 90 
hard, use of, as fuel, 332 
melting with, 130 
Cogniardelle, 294 

Coke, Connellsville, amount of, re- 
quired to melt iron, 90 
consumption of, in melting iron, 

332 
picking out of, from the dump, 

101 
use of, as fuel, 232 
Colliau cupola, claims for the, 194-196 
history and description of, 
193, 194 
patent hot-blast cupola, 192-196 
-Paxson cupola, 193. 194 

cupola, note on the, 345, 346 
tuyere, 41 
Combination stick, 93, 94 
Combustion, complete, 178 
Connersville cycloidal blower, 321-328 
Contact, point of, definition of, 323 
Continuous slot tuyere, 34, 35 
Copper, melting of, 223 
Corry, Pa., Pevie cupola at, 186 
Cost of melting, 230-232 
Crandall improved cupola with John- 
son patent center blast tuyere, 202- 
204 
Crates, iron, for removing the dump, 

100,101 
Crucible, experiments in a, with iron, 

130 
Cupola account, correctness of, 221 
accounts, 214-221 

manner of keeping, 214 
admission of air to the, 30 
and stack, weight of, 9 
banking a, 277-279 
best supports for a, 10 
Blakeney, 204, 205 
blower placed near, 290 
book, 231 



Cupola, boshed, burning out of the 
lining of the, 109 
new lining in, 105, 106 
boshing of, 14 
bottom, height of, 11 
brackets or angle iron for the 
support of the lining of a, 23, 24 
brick walls for the support of a, 10 
bridged sectional view of a, 107, 

lOS 
burning of iron in a, 88 
casing, construction of, 12 
cause of bridging and hanging 

up refuse in a, 99, 100 
charging a, 80-82 
chipping out the, 101-103 
Colliau patent hot blast, 192-196 
combined tuyere area of a, 49, 50 
commencement of melting in a^ 

86 
construction of a, 8-29 
Crandall improved, with Johnson 
patent center blast tuyere, 202- 
'204 
determination of the location of 

the melting zone in a, 123 
does it pay to slag a? 141, 142 
dumping the refuse from the, 98 
economical melting in a, 335 
effect of limestone in a, 138 
expanding, 155-157 
experiment to learn at what point 

of the, iron melts, 114 
experimental, 114 
for melting tin-plate scrap, 227, 

228, 229 
for tin-plate scrap, best lining 

material for a, 342 
foundation, 2, 9, 10 
furnace, 1-7, 332 

advantages of, 1 
chief use of, 223 
consumption of coke in, 

332 
description of, 2 
fuel required in, 1 
supply of air to the, 30 
Greiner patent economical, 188- 

192 
hardening of iron in a, 88 
height of a, 13 

the bottom of, 3 
Herbertz, 173-182 

for melting steel, 182-184 
highest, in use, 335 
holding molten iron in the, 88 
house, novel plan of construction, 
of a, 27,28 



INDEX. 



351 



Cupola, how to slat; a, 140, 141 

introductiou of the bottom sand 

into the, 63, 64 
Ireland's, 157-159 

center blast, 159—161 
iron support for a, 10 
Jumbo, 19S-202. 3)8 
large, lighting up a, 76 
learning to manage a, 209, 210 
length of time the blast can be 

taken off a, 276, 277 
lining, life of, 110 

renewal of, 12 
locating the tap hole in the, 7o 
location of, 8 

of slag hole in a, 74, 75 
Mackenzie, 170-17o 
management, 58-112 
means of supplying air to a, 294 
melting capacity of, 14, oO 

iron in a, terms used to in- 
dicate, 389 
tin-plate scrap in a, 225-229 
zone or melting point of a, 
77 
modern, casing or shell of, 12 
necessity of learning the peculiar- 
ities in the working 
of every, 58 
understanding the, to 
do good melting, 207 
newly lined, trouble in melting in 

a, 79 
number of Lours a, will melt iron 

freely, 224 
old, theory of melting in the, 296 
style, construction of, 149-152 
English, 154, 155 
spark catcher in, 263, 264 
picks. 102. 103 
pit of, 3, 4 

Paxson-Colliau, 193, 194 
Pevie, 184-186 
placing charges in the, 82-84 

tuyeres in a, 20, 21 
point of melting in a, 113 
practical instructions for charg- 
ing and managing a, 129 
working of a, 81 
preparation of a, for a heat, 208 
putting in two fronts and tap 

holes in a, 73, 74 
record, accurate, 337 
requirements of the foundryman 

from" the, 91 
requisites for melting iron in a, 

332, 333 
report, Abendroth Bros., 214,215 



Cupola report, Byrani & Co's, 214, 216 

reports, misleading, 90 
unrelialjility of, 344 

reservoir, 152, 153 

restriction to the passage of air 
through the, 294 

rule for charging a, 333 

scrap, charging of, 83 

scraps, 339-345 

sectional view of a, at Cincinnati, 
251 , 252 

size and weight of a piece of cast 
iron that can be melted in a, 224 

slate for charging, and cupola re- 
port, 220 

small, lighting up a, 76 

space of melting iron in a, 77 

spout, old way of making, 67 

stationary bottom, 154, 155 

Stewart's, 186-188 

stopping in a, 88 

straight, adhesion of slag and 
cinder to the lining of, 106 

supports of, 2, 3 

tank or reservoir, 167-170 

tendency of slag and cinder in a, 
136.137 

tuyeres, 30-57 

two-hour, 170 

Voisin's, 161-163 

warming up a, 248-250 

waste heat from a, 274, 275 

weight of slag drawn from a, 137, 
138 

what a, will melt, 223, 224 

Whiting, 196-198 

with tuyeres near the top, 129 

Woodward's steam jet, 163-167 
Cupolas, amount of fuel required for 
the bed of, 79 

and cupola practice up to date, 
3.32-338 

casings of, 2 

connection of blast pipes with, 284 

different styles of, 149-205 
ways of charging, 113 

fluxing of iron in, 135-148 

for heavy work, location of tuy- 
eres in, 53 

height and size of door for, 13, 14 
of tuyeres in, above sand 
bottom, 19, 20 

hot blast, 271-275 

in machine and jobbing found- 
ries, location of tuyeres in, 53 

large, tap-holes for, 16, 17 

location of a greater number of 
tuyeres in, 54 



352 



INDEX. 



Cupolas, melting of lead in, 223-224 
mistake of placing small tuyeres 

in, 49 
modern, spark catching device 

for, 2G4-26G 
number of tuyeres in, 2 
odd-shaped, shaping the linine 

of, 1U9 
of large diameter, location of 

tuyeres in, 52 
of very small diameter, location 

of tuyeres in, 52, 5^ 
old style, 149-152 
patent, shaping the lining of, 109 
props for, IJO, 61 
shapes of, 2 
size of, 33o 
sizes of, 2 
small, bod for, 95 

breaking away the bridge 

in, 99 
dumping of 99 
support of the stock in, 60 
tap hole for, 16 
smaller, location of tuyeres in, 

52 
spark catching devices for, 263- 

270 
table of speed and capacities of 

blowers as applied to, 3U9 
use of limestone in, 136 
with high tuyeres, impossibility 
of making hot iron for light 
work in, 52 
with two tap holes, slope of bot- 
tom in, 67 
Cylinder blower, 294 
Cycloidal blowers, numbers, capaci- 
ties, etc. , of, 326 
curves, 322 

DAUBING, 103-105 
application of, 105 
object of application of, to a 

lining, 105 
poor, cheap, nothing gained by 

using, 104, 105 
substances used for, 103 
thickness of, on a lining, 107 
wet, explosion of iron by, 262 
Detroit, Mich., novel plan of con- 
struction of a scaffold and cupola 
house at, 27, 28 
Diamond Drill and M'f'g Co., Birds- 

boro, Pa., cupola of the, 46 
Doherty tuyere, 33, 34 
Door, charging, 6, 14 

location of, 13 



Door, for cupolas, height and size of, 

13, 14 
Doors, bottom, 11, 12 

devices for raising the, 133, 
134 

devices for raising the, in place, 
59. 60 

dropping the, 61, 62 

heavy, best device for raising, 134 

putting up the, 59-61 

sliding, 4 

small, device for raising, 134 

supports of, 60 
Double tuyere, 42, 43 
Drying the lining, 58, 59 
Dump, breaking up the, 101 

chilling the, 99 

constitution of the, 100 

handling of the, 100 

picking over the, lOl 

removing the, 11, 100, 101 
Dumping, 98-100 

ELEVATOR, 9 
Elizabethport, N. J., tests with 
the Herbertz cupola at, 176, 
179-182 
England, Ireland's cupola patented 
in, 157 
use of tanks in, 169 
English cupola, old style, 154, 155 
Expanded tuyere, 32, 33 
Expanding cupola, 155-157 
Experiments in melting, 113-134 
Explosion of molten iron, 257-262 
Explosions in blast pipes, 292 

blast gauges, 
blast in 
melting, 
276, 277 

FAN blower. Smith's Dixie, 309-311 
Fire clay for daubing, 104 
soaking of, 104 
Fire-proof scaffold, 26-29 
Floor, explosion of iron by falling 

upon the, 258 
Fluor spar, 116, 147 
Flux, charging of, 84, 85 
definition of, 135 
effect of, upon iron, 138 
fluor spar as a, 146, 147 
quantity of, required, 84 
Fluxes, action of, on lining, 139 
materials used as, 135 
mineral, effect of, on a front ma- 
terial, 72 
use of, 135 



INDEX. 



353 



Fluxing, improper, injury to iron by, 
143,144 
of iron in cupolas, 135-148 
tin-plate scrap, 228 
Foundation, block in the, to rest the 
prop upon, 60 
construction of, 10 
cupola, 2, 9, 10 
Foundries, disturbances in melting 
in, 205 
number of men employed in, 230 
Foundry blowers, speed of, 820, 321 
standard, driven by pul- 
ley, table of dimen- 
sions of, in inches, 319 
department, Lebanon Stove 

Works, daily report of, 217 
Outfitting Co., Detroit, Mich., 
cupola manufactured by, 202- 
204 
result of keeping an accurate 

melting account in a, 231 
work, furnaces employed for, 332 
general, best practical results 
for melting for, o4o 
Foundry man, requirements of the, 

from the cupola, 91 
Foundrymen, theory of melting not 

understood by, 212 
Forced blast pressure blowers, 311- 

331 
Front, 71-73 

drying of the, 72 
material, effect of mineral fluxes 
on, 72 
for putting in the, 71 
poor, effect of, 72 
too wet, effect of, 72 
putting in the, 71 
thickness of, 72 
Fuel, 90-92 

air required for the combustion 

of, 295, 296 
amount of, in each charge, 81 
required for a bed, 79 

in each charge, 336 
and iron, division of, into 

charges, 212 
arranging the, for lighting up, 76 
consumption of too great an 
amount of, 336 
under the tuyeres, 
50, 51 
depth of, in the bed, 78 
distribution of the charge of, 83 
eflfect of too large a quantity of, 
in a bed, 128 
much, 230, 231 

23 



Fuel, guessing the weight of, 212 

heated, passage of blast through, 

127 
heating of, in a cupola, 129 
measuring of, 230 
old way of placing the, in the 

cupola, 80 
proportion of, to iron for melting, 

90 
quantity of, for a bed, 336 
required in various furnaces, 1 
too heavy charges of, effect of, 81 
too light charges of, effect of, 81 
under the tuyeres, 121, 122, 334 
value of, wasted every year in 

the United States, 53 
waste of, 341 
weight of the charges of iron to 

the charges of, 82 
Furnace, blast, definition of a, 136 

use of limestone in the, 
135, 136 
cupola, 1-7, 332 
kinds of, 332 
pot, 332 

reverberatory, 332 
Furnaces, various, fuel required in, 1 

GAIvVANIZED sheet iron scrap, 342 
melting 
of, 227 
Garden City positive blast blowers, 

328, 329 
Gas, preventing the passage of, into 

the blast pipe, 85 
Gases, escaping, composition of, 177, 
178 
free oxygen in the, 178 
Gates, charging of, 83 
Gauges, blast, 292-294 
Glasgow, Scotland, use of Stewart's 

cupola at, 186-188 
Gould & Fberhardt, scaffold in the 

foundry of, at Newark, N. J., 28 
Green patented positive pressure 

blower, 314-321 
Greiner patent economical ciipola, 
188-192 
tuyere, 45 
Grout, composition of, 6 
Grouting for lining, 22 

HEARTH in the Herbertz cupola at 
Elizabethport, N. J., 180 
movable, of the Herbertz 
cupola, 173 
Heat, escaping, attempts to return 
the, to the cupola, 273, 274 



354 



INDEX. 



Heat, make a, 339 
take a, 339 
taking off the blast during a, 276- 

299 
theory of the production of, 44, 45 
utilization of, 275 
waste, from a cupola, 274, 275 
plans for the utilization of, 

271 
utilization of, 1, 2, 13 
Heats, experimental, charges for, 

126, 127 
Height of cupola bottom, 11 

tuyeres, 50-53 
Herbertz cupola, 173-182 

for melting steel, 182- 

184 
test-heats with the, 176, 
177 
Hibler, B. H., bottom tuyere patented 

by, 48 
Horizontal and vertical slot tuyere, 
36,37 
blower, 325 
slot tiiyere, 34 
Horse manure as an essential of a 

good bod, 95 
Hot blast cupolas, 271-275 

I MPEIvLER, complete, 316 
1 Iron, additional, charging of, 83 
affinity of limestone for, 136 
amount of anthracite coal re- 
quired to melt, 90 
combined with the 

slag, 142 
Connellsville coke 
required to melt, 
90 
limestone required 

for, 137 
placed upon the 
bed in the first 
charge, 81 
and fuel, division of, into 

charges, 212 
arrangement of, in the experi- 
mental cupola, 114-119 
art of melting, 211, 212 
burning of, in a cupola, 88 
carbonized, use of, as softeners, 

145 
cast, effect of carbon upon, 145 
quantity of, that can be 

melted in a cupola, 224 
size and weight of a piece 
of, that can be melted in 
a cupola, 224 



■Iron, cause of the variations in the 
weight of the first charge of, 
82 
change in the action of the, at 

the spout, 66 
charging, 340, 341 

large pieces of, 224 
cleaning of, by boiling, 147, 

148 
consumption of coke in melt- 
ing, 332 
contents of, in slag, 138 
cost of melting, 342 
cubic feet of air required to 

melt a ton of, 293, 294 
deception in the quality of the, 

at the spout, 66 
dull, cause of, 336 
effect of flux upon, 138 
silicon on, 144 
tin on, 227 

too heavy a charge of, 
128 
experiments in softening with 
charcoal 130-132 
with, in a crucible, 
130 
explosion of molten iron, by, 

258, i'59 
first melted, chilling and hard- 
ening of, 87 
fluxing of, in cupolas, 135-148 
furnaces employed in melting 

of, 332 
guessing the weight of, 212 
hard, experiments in softening, 

51 
hard, softening, 130-132 

sparks from, 258 
hardening of, in a cupola, 88 
high silicon, Southern, use of, 

in stove foundries, 144, 145 
hot and of even temperature, 
melting of, 208 
for light work, impossibil- 
ity of making, in cupolas 
with high tuj'cres, 52 
impossibility of melting, under 

the tuj-eres, 51 
improvement of, in a cupola 

furnace, 143 
indication of the melting by the 
flow of, from the tap hole, 
88, 89 
injury to, by improper melting 

and fluxing, 143, 144 
malleable, experiments in mak- 
ing, 143 



INDEX. 



355 



Iron, melted high in a cupola, cause 

of dullness of, 128 
V melting of, correct theory of, 80 

in a cupola, no chance 
work in, 207 
terms used to 
indicate the, 
339 
things to be learned in, 
209 
molten, explosion of, 64, 65, 
257-262 
filtering of, through slag, 

84. 85 
handling of, 341 
holding of, in the cupola, 

88 
poling of, 147, 148 
number of hours a cupola will 

melt, 224 
old way of placing the, in the 

cupola, 80 
over, mould for, 222 
picking out of, from the dump, 

101 
placing the first charge of, on 
the bed, 80 
in the cupola, 83 
point of melting, in a cupola, 

113 
proportion of fuel to, for melt- 
ing, 90 
recovery of, from the dump, 

101 
removal of carbon from, 1-15 
requisites for melting, in a cu- 
pola, 332, 333 
space of melting, in a cupola, 77 
theory of preventing, from run- 
ning into the tuyeres, 102 
time for charging, 132, 133 

the, before the 

blast is put on, 

86, 87 

too heavy charges of, effect of, 

81 

light charges of, effect of, 81 

tuyeres to improve the qualitv 

of, 55, 56 
weight of the charges of, to the 
charges of fuel, 82 
first charge, 81 
Ireland, Mr., bottom tuyere used by, 
48 
double or two rows of 
tuyeres devised by, 42 
Ireland's center blast cupola, 159-161 
cupola, 157-159 



Isbell Porter Co., Newark, N. J., blower 
built by the, 
312 
Mackenzie cu- 
pola, manu- 
factured b}-, 
170-173 

J AGGER, Treadwell & Perry, cupo- 
las constructed by, 271-273 
Jamestown, N. Y., tuyeres in a cupola, 

31 
Jobbing foundry cupolas, location of 

tuyeres in, 53 
Johnson, Mr., experiments of, with 

the center blast tuyere, 299 
Johnson, John D., & Co., Hainesport, 
N. J , action of fluxes on lining of 
cupola of, 139 
Jumbo cupola, 198-202, 298 

table of charges of, 200 

KNOEPPEL, Mr., on banking a 
cupola, 277-279 

LADLE, damp, iron caused to boil 
by a, 262 
Lawrence reducing tuyere, 38, 39 
Lead, melting of, in cupolas, 223 

molten, handling of, 342 
Leather bellows, 294 
Lebanon Stove Works, daily report of 

foundry department of, 217 
Light-up, bad, 340 
Lighting-up, 76, 77 

wood for, 340 
Limestone, action of a large per cent, 
of, 137 
affinity of, for iron, 136 
amount required of, 137 
charging of, 140 
effect of, in a cupola, 138 
in large quantities, 136-138 
object of use of, 136 
use of, in blast furnace, 135, 136 
cupolas, 136 
Lining, 21-23 

action of fluxes on, 139 

belly of, 107 

brackets or angle iron for the 

support of the, 2:>, 24 
burning away of the, at the melt- 
ing zone, 110 
out of, 24, 25 
cupola, life of, 110 
destruction of, at and below the 

tuyeres, 110 
drying the, 58, 59 



356 



INDEX. 



Lining, effect of fluor spar on the, 140 
too much clay in, 68 
sand in, 68 
false, 22, 111,112 
filling in the, at the melting zone, 

106, 107 
greatest wear of, 110 
laying up a, 22 
material, best, 342 

for spouts, 68 
new, in cupola, 105, 106 
object of applying daubing to a, 

105 
of boshed cupola, burning out of 

a, 109 
old, false lining over the. 111, 

112 
out of shape, sectional view of, 

1135. 237, 239, 241 
prevention of absorption of mois- 
ture by the, 25, 26 
refractory material for, 6, 7 
renewal of, 12 
selection of a, 139 
settling of, 25 
shaping the, 105-110 
split brick, 112 
spout, 67 

stack, wear of, 110 
support of 5 
taper of, 107 

to the, from the bosh, 109 
thickness of 22, 110 

daubing on a, 107 
to protect the casing, 
111 
v/ear of, at the charging door, 110 
Loading, old way of, 80 
Loam clays lor spout lining, 67 

sands, 62 
Loams for bods, 94 
Lobdell Car Wheel Co., Wilmington, 
Del., melting cannon at the foundry 
of, 224 
Low tuyeres, 122, 123 

McGILVERY, WM. & CO., acci- 
dent in the foundry of, 259, 260 
Machine foundry cupolas, location of 

tuyeres in, 53 
Mackenzie blower, 311-314 
cupola, 170-173 
tuyere, 34, 35 
Magee Furnace Co., Boston, Mass., 

triangular tuyere used by the, 39 
Malleable iron, experiments in mak- 
ing, 143 
Marble spalls, 142, 143 



Marsh, James, explosion of iron in 

the foundry of, 1:60 
Massachusetts, early use of bottom 

tuyere in, 48 
Melt, run a, 339 
Melter, aim of every, 255, 256 
directions by the, 210 
good, interference with a, 254,255 
poor, 254 

practical and scientific, 254 
process of chipping out by the, 

101-103 
skill of the, seen at the tap hole, 98 
whims of, 210 
Melters, 254-256 

no attention paid by many, to 

shape the cupola, 105 
theory of some, 102 
Melting, 86-89 

account, accurate, result of keep- 
ing a, 231 
art in, 205-210 
bad, cause of, 247 

caused by wood and coal, 

250, 251 
examples of, 233-253 
best practical results for, 343 
blast in, 294-299 

capacity, increase in the, by two 
or three rows of tuyeres, 21 
of a cupola, 30 
commencement of, 86 
cost of, 230-232 

per ton, mode of figuring, 
231,232 
disturbances in, 205 
economical, 335 
experiments in, 113-134 
fast, 207 

galvanized sheet-iron scrap, 227 
good, necessity of understanding 

the cupola for, 207 
improper, injury to iron by, 143, 

144 
indication of the, by the flow of 

iron from the tap hole, 88, 89 
iron, art of, 211. 212 

correct theory of, 80 
cost of, 342 

hot and of an even tempera- 
ture, 2(i8 
in a cupola, no chance work 
in, 207 
terms used to in- 
dicate the, 339 
things to be learned in, 209 
most even, charges for, 127 
point, 77 



INDEX. 



357 



Melting point, discovery of the, 77 
in a cupola, 113 
to find the, 78 
poor, caused by long blast pipes, 
290 
due to the bed being burned 

too much, 240, 25(i 
in a Cincinnati cupola, 251- 
253 
preparation of tin-plate scrap for, 

225 
reduction of, to a system, 214, 337 
scrap sheet iron, 227 
sheet of Syracuse Stove Works, 

218 
slow, 207, 208 

and irregular, 337 
cause of, 337 
study of the materials used in, 209 
theory of, in the old cupola, 296 
not understood by foun- 
dry men, 212 
tin-plate scrap, cost of, 342 

experiments in, 226. 

227 
in a cupola, 225-229 
with coal, 130 
zone, 77, 123-129 

burning away of the lining 

at the, 110 
depth of, 125 

determination of the location 

of the, 

123, 335 

topof,335, 

336 

development of the, 129 

filling in the lining at the, 

106,107 
location of the, 77 
raising and lowering the, 120, 
123 
Mercury gauges, 292 
Metal from tin plate scrap, doctoring 
of, 227 
quality of, 
225, 226 
gray, from tin-plate scrap, 226 
Moisture, prevention of the absorp- 
tion of, by the lining, 25, 26 
Molding sand for spout lining, 07 
Molten iron, explosion of, 257-262 
Mould for over iron, 222 
Moulder, aim of every, 210 
Moulding, 339 

floors, cleanings from, 63 
sand, use of, for daubing, 103 
sands for bods, 94 



M. Steel Co., Springfield, O., Blakeney 
cupola man- 
ufactured by 
the, 204,205 
tuyere used in 
the cupola, 
constructed 
by the, 35, 36 

Mud, explosion of iron when poured 
into, 260 

NAU, J. B., on the Herbertz cupola, 
173-182 
North Bros., explosion of iron in the 
foundry of, 260, 261 

O'KEEFE, J., spark catcher, de- 
signed by, 266-2()8 
Oval tuyere, 32 
Over iron, mould for, 222 
Oyster shells, 142 

Oxygen, free, in the escaping gases, 
178 

PARIS, D. E., & CO., West Troy, 
N. Y., bad melting at the foundry 
of, 242-248 
Paxson-Colliau cupola, 193, 194 

note on the, 345, 
346 
Perry & Co., cause of having to dump 
a cupola at the foundry 
of, 253 
examples of bad melting 
at the foundry of, 233- 
242 
Pevie cupola, 184-186 
Picks, cupola, 102, 103 
[ Pig iron, placing the, in the cupola, 
I 82, 83 

' Pipe, main, perfect manner of con- 
j necting the, with an air chamber,290 
I Pipes, blast, 279-281 
I branch, area of, 284 

I friction of air in, 281-282 

i Piston blower, 294 
Pit, cupola, 3, 4 
Pit lining, 3 
Platform scales, 21 1 
Point of contact, definition of, 323 

melting, discovery of the, 77 
Poking the tuyeres, 89 
Poling molten iron, 147, 148 
Poor melting in a Cincinnati cupola, 

251-253 
Pot furnace, 332 

consumption of coke in, 332 
fuel required in, 1 



358 



INDEX. 



Power, rule for estimating the amount 
of, to displace a given amount of 
air at a given pressure, 318 

Pratt & Whitney, charging large 
pieces of iron at the foimdry of, 224 

Props, 60, 61 

removing the, 61 , 62, 99 

Providence Locomotive Works, visit 
to the plant of, 248-250 

RANSOM & CO., Albany, N. Y., 
cupola at the stove foundry of, 273 
Records, blanks for, 221 

value of, 214 
Reducing tuyere, Lawrence, 38, 39 

Truesdale, 37, 38 
Refractory material for lining, 6, 7 
Relining and repairing, 110-112 
Repairing and relining, 110-112 
Report, cupola, Abendroth Bros.', 214, 
215 
Byram&Co.'s, 214,216 
daily, of Foundry department 

Lebanon Stove works, 217 
of castings, 219 
Reports, blanks for, 221 
false, 221 
keeping of, 221 
Reservoir cupola, 152, 153 

or tank cupola, 167-170 
Return flue cupola spark catcher, 

266-268 
Reverberatory furnace, 332 

consumption o f 

coke in, 332 
fuel required in, 1 
Reversed T tuyere, 37 
Richmond, Ind., sectional view of a 

bridged cupola at, 107, 108 
Riddles, increase in size of, 212 
Roots's rotary positive pressure 

blower, 329-331 
Round tuyere, 31, 32 

ST. LOUIS, MO., large cupola with 
two tuyeres in, 54 
Sand, amount of, in clay for daubing, 
104 
bottom, 62-67 

destruction of the, 64 
elements to contend with 

in the, 65 
height of tuyeres above, 

19,20,3.33,334 
leakage of, 64 
perfect joint between the, 
and the spout lining, 68, 
69 



Sand bottom, pitch or slope of, 64 
riddling out of the, 101 
slushing the, 64 
effect of too much, in lining, 68 
for bottom, working of, 65 
for sand-bottom, 62 
mould, explosion of iron in a, 259 
moulding, use of, for daubing, 103 
sharp, for daubing, 104 
Sash weights, 226 
Scaffold, 7, 8, 9 

construction of, 9 

distance of the floor of, below the 

charging door, 26 
exposure of, to fire, 26, 27 
fire proof, 9 
location of, 26 
novel plan of construction of a, 

27.28 
old worn-out scales upon the, 213 
scales in the floor of, 211 
Scaffolds, best and safest, 28, 29 

devices for rendering fire-proof, 
27,28 
Scale, size of, 211 
Scales aud their use, 211-213 

old worn-out, 213 
Scrap, charging of, 83 

galvanized sheet iron, melting 

of, 227 
heavy government melting of, 224 
rusted, explosion of iron when 
brought in contact with, 260, 
262 
sheet iron, melting of, 227 
tin-plate, cupola for melting, 227, 
228. 229 
experiments in melting, 

226, 227 
fluxing of, 228 
melting of, in a cupola, 

225-229 
preparation of, for melt- 
ing, 225 
Shaping the lining, 105-110 
Shavings for lighting up, 76 
Sheet blast tuyere, 34 

iron scrap, galvanized, melting 
of, 227 
melting of, 227 
Shells, 142 

crackling of, 142 
Silicon, effect of, on iron, 144 
Size of tuyeres, 49, 50 
Skinner Engine Co., explosion in the 

the cupola of, 261, 262 
Slag, amount of iron combined with 
the, 142 



INDEX. 



359 



Slag, chilling of, 75 
chipping off, 106 
closing up of the tap hole with, 

339 
contents of, 138 
filtering molten iron through, 84, 

85 
formation of, in a spout, 339 
hole, 74, 75 
front, 75 

location of the, 17, 18, 140, 
141 
impurities in the, 141 
in cupola, breaking down the, 102 
position of, in the cupola, 18 
removal of, from the spout, 70 
tapping of, 17, 51, 53 
tendency of, in a cupola, 136, 137 
time for drawing of, 1 41 
weight of, drawn from a cupola, 
137, 138 
Slagging a cupola, 140, 141 
cost of, 141, 142 
saving effected by, 141 
trouble in, 140 
Slate, cupola, for charging, and cupola 

report, 220 
Sledging, bars for, 92 
Sliding doors, 4 

Smith's Dixie fan blower, 309-311 
Smithfield, N. J., Pevie cupola at, 186 
Soapstone for daubing, 104 
Softening hard iron, 130-132 
Spark catcher, return flue cupola, 
266-268 
catching device, best, 269, 270 

for modern cupolas, 

264-266 
oldest and most eflS- 
cient, 263, 264 
devices for cupolas, 263-270 
various, 268, 269 
Sparks, 258, 342 

objections to, 5 
Speed of foundry blowers. 320-321 

ordinary, definition of, 326 
Split-brick, 112 
Spout, 17, 18, 67-70 

building the sides of the lining 

of, 69 
change in the action of the iron 

at the, 66 
choking up of the, 69 
coating of the, 70 
damp, boiling of iron in a, 257 
deception in the quality of the 

iron at the, 66 
formation of slag in a, 339 



Spout, lining, 67 

cutting out of the, in holes, 

339 
drying of the, 72 
greatest strain upon the,69,70 
making up of the, 68 
perfect joint between the,and 
the sand bottom, 68, 69 
old way of making, 67 
removal of slag from the, 70 
shaping the lining of the, 70 
size of, 17 

wet, explosion of iron in a, 257 
with a broad flat bottom, 339, 340 
Spouts, lining material for, 68 
modern, 67 

short, common practice in, 69 
Stack and cupola, weight of, 9 
casing. 2. 5 

construction of, 12 
contracted, 5 
contraction of, 12 
enlarged, 5, 269 
enlarging of, 12, 13 
height of, 5 
lining, renewal of, 12 
thickness of, 22, 23 
wear of, 110 
size of, 5 
Standard foundry blowers driven by 
pulley; dimensions in inches, table 
of, 319 
Stationary bottom cupola, 154, 155 
Steam jet, advantages of the, 175 

cupola. Woodward's, 163-167 
Steel, Herbertz cupola for melting* 
182-184 
spring gauges, 292 
Stewart's cupola, 186-188 
Stocking, modern way of, 80 

old way of, 80 
Stopping-in and tapping, 96-98 
devices to assist in, 97, 98 
difficulties in, 97 
knack in, 97 
mode of, 97 
Stove foundries, breakage in, 145 

height of tuyeres in, 20 
sand for bottom used in, 

62, 63 
use of high silicon South- 
ern iron in, 144, 145 
Straight Line Engine Co., Syracuse, 
N. Y., scaffold in the foundry of, 
28,29 
Straw for lighting up, 76 
Syracuse Stove Works, melting sheet 
of, 218 



36o 



INDEX. 



TABLE of diameter aud area of blast 
pipes, 2S5 
speed and capacities of 
blowers as applied to 
cupolas, 309 
standard foundry blowers 
driven by pulley; di- 
mensions in inches, 319 
showing the necessary increase 
in diameter for the different 
lengths of blast pipes, 283 
Taking off the blast during a heat, 

276-299 
Tank or reservoir cupola, 167-170 
Tanks, use of, in England, 169 
Tap-hole, 16, 17 

chilling of slag in the, 75 
closing up of the, with slag, 339 
indication of the melting by the 

flow of iron from the, 88, 89 
skill of the melter seen at the, 98 
mode of forming, 71 
preventing the cutting of, 73 
reducing the size of the, 87, 88 
sizes of, 73 
too long, effect of, 72 
Tap-holes, locating the, 17, 73, 74 
Tap, making a, when iron is handled 
in large ladles, 87 
mode of making the, 96, 97 
Tapping and stopping in, 96-98 

bar, explosion of iron caused by, 
258 
Tapping bars, 92, 93 

burning up the, 341 
Tin deposited upon iron, recovery of, 
225 
effect of, on iron, 227 
-plate scrap, 342 

cost of melting, 342 
cupola for melting, 227, 

228 
doctoring metal from, 227 
experiments in melting, 

226, 227 
fluxing of, 228 
gray metal from, 226 
loss of metal in melting, 

342 
melting of, in a cupola, 

225-229 
preparation of, for melt- 
ing, 225 
quality of metal from, 
225 226 
Treat, C. A., remarks of, 344 
Triangular tuyere, 39 
Trompe, 294 



Trucks for removing the dump, 100 
Truesdale reducing tu3'ere, 37, 38 
Tuyere area, combined, of a cupola, 
49, 50 
Blakeney, 35,36 
bottom, 46-49 
boxes, 19, 56, 57 
Cheuney, 42 
Colliau, 41 

continuous slot, 34, 35 
Doherty, 33, 34 
double, 42, 43 
expanded, 32, 33 
expanding, 297 
Greiner, 45 
horizontal and vertical slot, 36, 37 

slot, 34 
invention, epidemics of, 30, 31 
Lawrence reducing, 38, 39 
Mackenzie, 34, 35 
outlet area of a, 297 
oval, 32 
reversed T, 37 
round, 31 , 32 
sheet blast, 34 
triangular, 26, 39 
Truesdale reducing, 37, 38 
vertical slot, 37 
water, 40, 41 
Whiting, 41 
Tuyeres, 18-20 

adjustable, 45, 46 

air chamber for supplying the, 

with blast, 14 
center blast, experiments with, 

298, 299 
connecting blast pipes direct with, 

from a belt air chamber, 286-290 
connection of, with the blower, 5 
consumption of fuel under the, 

50,51 
cupola, 30-57 
destruction of the lining, at and 

below the, 110 
direct delivery of blast to, 284 
fuel under the, 121, 122, 334 
general improvement made in, 

341 
height of, 50-53 

above sand bottom, 19, 
20, 333, 334 
high, 341 

reason in favor of, 51 
increase in the melting capacity 

by two or three rows of, 21 
liability of, to be closed, 50 
location of, 18, 19 
low. 122, 123 



INDEX. 



361 



Tuyeres, number of, in a cupola, 2, 

18, 19,54,55 
placing of, in a cupola, 20, 21 
poking the, 89 
projection or hump on the lining 

over the, 102 
shape of, 19. 55 
size of, 49, 50 
small, objection to, 49 
theory of preventing iron from 

running into the, 102 
three rows of, 43-45 
to improve the quality of the iron, 

55,56 
triangular, 297 
two rows of, 42, 43 

or more rows of, 20, 21 
vertical slot, 297 
very best way of connecting blast 

pipes with, 288-290 



VERTICAL blower and engine on 
same bed plate, 326 
slot tuyere, 37 
Voisin, bottom tuyere used by, 48 
Voisin's cupola, 161-163 

double tuyere used in, 
42 



WARMING up a cupola, 248-250 
Waste heat from a cupola, 274,275 
utilization of, 12, 13 
Water blast, 294 

cylinder blast, 294 
gauges, 292 
tuyere, 40, 41 



West, Thomas D., experiments with 
the bottom 
tuyere by, 
48,49 
with the 
centerblast 
tuyere, 299 
West Troy Stove Works, bad melting 

at a, 242-248 
Whiting cupola, 196-198 

Foundry Equipment Co., Chicago, 

tuyere manufactured by the, 41 

Wilbraham-Baker Blower Co., blower 

built by the, 314-321 
Wood and coal, bad melting caused 
by, 250, 251 
arranging the, for lighting up, 76 
for lighting up, 340 
Woodward's steam-jet cupola. 163-167 
double tuy- 
ere used 
in, 42 

ZINC, effect of, on the fire in the 
cupola, 227 
Zone, melting, 77, 123-129 

burning away of the lining 

at the, 110 
depth of, 125 

determination of the loca- 
tion of the, 1 23 , 335 
of the top of, 335,336 
development of the, 129 
filling in the lining at the, 

106, 107 
location of the, 77 
raising and lowering the, 
120,123 



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Drainage, Painting and Landscape Gardening. By John Bullock, 
Archite«t and Editor of " The Rudiments of Architecture and 
Building," etc., etc. Illustrated by 75 engravings. Svo. ^2.50 

BULLOCK. — The Rudiments of Architecture and Building: 
For the use of Architects, Builders, Draughtsmen, Machinists, En- 
gineers and Mechanics. Edited by John Bullock, author of " The 
American Cottage Builder." Illustrated by 250 Engravings. Svo. ^2.50 

BURGH. — Practical Rules for the Proportions of Modem 
Engines and Boilers for Land and Marine Purposes. 
By N. P. Burgh, Engineer. i2mo. .... ^1.50 

BYLES.— Sophisms of Free Trade and Popular Political 

Economy Examined. 

By a Barrister (Sir John Barnard Byles, Judge of Common 

Pleas). From the Ninth English Edition, as published by the 

Manchester Reciprocity Association. i2mo. . . . ^1.25 

BOWMAN.— The Structure of the Wool Fibre in its Relation 
to the Use of Wool for Technical Purposes : 
Being the substance, with additions, of Five Lectures, deliverea at 
*he request of the Council, to the members of the Bradford TechnicaJ 
College, and the Society of Dyers and Colorists. By F. H. Bow- 
MAN, D. Sc, F. R. S. E., F. L. S. Illustrated by 32 engravings. 
Svo ^5.00 

BYRNE. — Hand-Book for the Artisan, Mechanic, and Engi- 
neer: 
Comprising the Grinding and Sharpening of Cutting Tools, Al)i£-.ve 
Processes, Lapidary Work, Gem and Glass Engraving, Varnishing 
and Lackering, Apparatus, Materials and Processes for Grinding and 



HENRY CAREY BAIRD & CO.'S CATALOGUE. 



Polishing, etc. By Oliver Byrne. Illustrated by 185 wood en- 
gravings. 8vo. 55-O0 

BYRNE. — Pocket-Book for Railroad and Civil Engineers: 

Containing New, Exact and Concise Methods for Laying out Railroad 
Curves, Switches, Frog Angles and Crossings ; the Staking out of 
work ; Levelling ; the Calculation of Cuttings ; Embankments ; Earth- 
work, etc. By Oliver Byrne. iSmo., full bound, pocket-book 
form $l.So 

BYRNE. — The Practical Metal- Worker's Assistant: 
Comprising Metallurgic Chemistry; the Arts of Working all Metalj 
and Alloys ; Forging of Iron and Steel; Hardening and Tempering; 
Melting and Mixing; Casting and Founding; Works in Sheet Metal; 
the Processes Dependent on the Ductility of the Metals; Soldering; 
and the most Improved Processes and Tools employed by Metal- 
workers. With the Application of the Art of Electro-Metallurgy to 
Manufacturing Processes ; collected from Original Sources, and from 
the works of Holtzapfifel, Bergeron, Leupold, Plumier, Napier, 
Scoffern, Clay, Fairbairn and others. By Oliver Byrne. A new, 
revised and improved edition, to which is added an Appendix, con- 
taining The Manufacture of Russian Sheet-Iron. By John Percy, 
M. D., F. R. S. The Manufacture of Malleable Iron Castings, and 
Improvements in Bessemer Steel. By A. A. Fesquet, Chemist and 
Engineer. With over Six Hundred Engravings, Illustrating every 
Branch of the Subject. 8vo. ...... ^5-00 

BYRNE.— The Practical Model Calculator: 
For the Engineer, Mechanic, Manufacturer of Engine Work, Naval 
Architect, Miner and Millwright. By Oliver Byrne. 8vo., nearly 
600 pages jj53,oo 

CABINET MAKER'S ALBUM OF FURNITURE. 
Comprising a Collection of Designs for various Styles of Furniture. 
Illustrated by Forty-eight Large and Beautifully Engray-'id Plates. 
Oblong, 8vo. ........ ^1.50 

CALLINGHAM.— Sign Writing and Glass Embossing: 

A Complete Practical Illustrated Manual of the Art. By James 
Callingham. i2mo ^1.50 

CAMPIN. — A Practical Treatise on Mechanical Engineering: 
Comprising Metallurgy, Moulding, Casting, Forging, Tools, Work, 
shop Machinery, Mechanical Manipulation, Manufacture of Steam* 
Engines, etc. With an Appendix on the Analysis of Iron and Iron 
Ores. By Francis Campin, C. E. To which are added. Observations 
on the Construction of Steam Boilers, and Remarks upon Furnaces 
used for Smoke Prevention ; with a Chapter on Explosions. By R, 
Armstrong, C. E., and John Bourne. Rules for Calculating th« 
Change Wheels for Screws on a Turning Lathe, and for a WheeU 
cutting Machine. By J. La Nicca. Management of Steel, Includ- 
ing Forging, Hardening, Tempering, Annealing, Shrinking and 
Expansion ; and the Case-hardening of Iron. By G. Ede. 8vo. 
Illustrated with twenty-nine plates and 100 wood engravings $S-00 



HENRY CAREY BAIRD & CO.'S CATALOGUE. 



CAREY.— A Memoir of Henry C. Carey. 

By Dr. Wm. Elder. With a portrait. 8vo., cloth . . 75 

CAREY.— The Works of Henry C. Carey : 

Harmony of Interests : Agricultural, Manufacturing and Commer- 
cial. 8vo. . . $1.25 

Manual of Social Science. Condensed from Carey's " Principles 
of Social Science." By Kate McKean. I vol. I2mo. . $2.00 
Miscellaneous Works. With a Portrait. 2 vols. 8vo. ;? 10.00 

Past, Present and Future. 8vo $2.50 

Principles of Social Science. 3 volumes, 8vo. . . $7-50 
The Slave-Trade, Domestic and Foreign; Why it Exists, and 
How it may be Extinguished (1853). 8vo. . . . #2.00 

The Unity of Law : As Exhibited in the Relations of Physical, 
Social, Mental and Moral Science (1S72). 8vo. . . ^2.50 

CLARK. — Tramways, their Construction and Working : 

Embracing Comprehensive History of the System. With an ex- 
haustive analysis of the various modes of traction, including horse- 
power, steam, heated water a:id compressed air; a description of the 
varieties of Rolling stock, and ample details of cost and working ex- 
penses. By D. KiNNEAR Clark. Illustrated by over 200 wood 
engravings, and thirteen folding plntes. I vol. 8vo. . ^7.50 

COLBURN.— The Locomotive Engine: 

Including a Description of its Structure, Rules for Estimating its 
Capabilities, and Practical Observations on its Construction and Man- 
agement. By Zerah CoLBURN. Illustrated. i2mo. . $l.oa 

COLLENS.— The Eden of Labor; or, the Christian Utopia. 
By T. Wharton Collens, author of " Humanics," " The Historj 
of Charity," etc. i2mo. Paper cover, $1.00 ; Cloth . ^1.25 

COOLEY.— A Complete Practical Treatise on Perfumery: 

Being a Hand-book of Perfumes, Cosmetics and other Toilet Articles, 
With a Comprehensive Collection of Formulae. By ARNOLD J 
Cooley. i2mo. ........ $i-S^ 

COOPER.— A Treatise on the use of Belting for the Trans- 
mission of Power. 
With numerous illustrations of approved and actual methods of ar- 
ranging Main Driving and Quarter Twist Belts, and of Belt Fasten 
ings. Examples and Rules in great number for exhibiting and cal- 
culating the size and driving power of Belts. Plain, Particular and 
Practical Directions for the Treatment, Care and Management o'' 
Belts. Descriptions of many varieties of Beltings, together witft 
chapters on the Transmission of Power by Ropes; by Iron and 
Wood Frictional Gearing; on the Strength of Belting Leather; and 
on the Experimental Investigations of Morin, Briggs, and others. Bf 
John H. Cooper, M. E. 8vo. ...... $i-5^ 

CRAIK. — The Practical American Millwright and MUler. 

By David Craik, Millwright. Illustrated by numerous wood en- 
gravings and two folding plates, 8vo $3'5° 



HENRY CAREY BAIRD & CO.'S CATALOGUE. 9 

CROSS.— The Cotton Yarn Spinner : 

Showing how the Preparation should be arranged for Different 
Counts of Yarns by a System more uniform than has hitherto been 
practiced; by having a Standard Schedule from which we make all 
our Changes. By Richard Cross. 122 pp. i2mo. . 75 

CRISTIANI.— A Tech-ical Treatise on Soap and Candles: 

With a Glance at the Industry of Fats and Oils. By R. S. Cris- 
TIANI, Chemist. Author of " Perfumery and Kindred Arts." Illus- 
trated by 176 engravings. 581 pages, 8vo. . . . ^15.00 

COAL AND METAL MINERS' POCKET BOOK: 

Of Principles, Rules, Formula?, and Tables, Specially Compiled 
and Prepared for the Convenient Use of Mine Officials, Mining En- 
gineers, and .Students preparing themselves for Certificates of Compe- 
tency as Mine Inspectors or Mine Foremen. Revised and Enlarged 
edition. Illustrated, 565 pages, small i2mo , cloth. . ^2.00 

Pocket book form, flexible leather with flap . . ^2.75 

DAVIDSON.— A Practical Manual of House Painting, Grain- 
ing, Marbling, and Sign- Writing: 
Containing full information on the processes of House Painting in 
Oil and Distemper, the Formation of Letters and Practice of Sign- 
Writing, the Principles of Decorative Art, a Course of Elementary 
Drawing for House Painters, Writers, etc., and a Collection of Useful 
Receipts. With nine colored illustrations of Woods and Marbles, 
and numerous wood engravings. By Ellis A. Davidson. i2mo. 

;jS2.oo 

DAVIES.— A Treatise on Earthy and Other Minerals and 

Mining: 
By I). C. Davies, F. G. S., Mining Engineer, etc. Illustrated by 
76 Engravings. i2mo. ....... ^5.00 

DAVIES. — A Treatise on Metalliferous Minerals and Mining: 
By D. C. Davies, F. G. S , Mining Engineer, Examiner of Mines, 
Quarries and Collieries. Illustrated by 148 engravings of Geological 
Formations, Mining Operations and Machinery, drawn from the 
practice of all parts of the world. Fifth Edition, thoroughly Revised 
and much Enlarged by his son, E. Henry Davies. i2mo., 524 
pages . . ^5.00 

DAVIES. — A Treatise on Slate and Slate Quarrying: 

Scientific, Practical and Commercial. By D. C. Davies, F. G. S., 
Mining Engineer, etc. With numerous illustrations and folding 
plates. l2mo. ........ ^2.00 

DAVIS. — A Practical Treatise on the Manufacture of Brick, 

Tiles and Terra-Cotta : 

Including Stiff Clay, Dry Clay, Hand Made, Pressed or Front, and 

Roadway Paving Brick, Enamelled Brick, with Glazes and Colors, 

Fire Brick and Blocks, Silica Brick, Carbon Brick, Glass Pots, Re- 



lo HENRY CAREY BAIRD & CO.'S CATALOGUE. 

torts, Architectural Terra-Cotta, Sewer Pipe, Drain Tile, Glazed and 
Unglazed Roofing Tile, Art Tile, Mosaics, and Imitation of Intarsia 
or Inlaid Surfaces. Comprising every product of Clay employed in 
Architecture, Engineering, and the Blast Furnace. With a Detailed 
Description of the Different Clays employed, the Most Modern 
Machinery, Tools, and Kilns used, and the Processes for Handling, 
Disintegrating, Tempering, and Moulding the Clay into Shape, Dry- 
ing, Setting, and Burning. By Charles 'Fhonias Davis. Third Edi- 
tion. Revised and in great part rewritten. Illustrated by 261 
engravings. 662 pages ....... $5-00 

DAVIS. — A Treatise on Steam-Boiler Incrustation and Meth- 
ods for Preventing Corrosion and the Formation of Scale: 
By Charles T. Davis. Illustrated by 65 engravings. 8vo. ^2.00 

DAVIS. — The Manufacture of Paper : 

Being a Description of the various Processes for the Fabrication, 
Coloring and Finishing of every kind of Paper, Including the Dif- 
ferent Ravi' Materials and the Methods for Determining their Values, 
the Tools, Machines and Practical Details connected with an intelli- 
gent and a profitable prosecution of the art, with special reference to 
the best American Practice. To which are added a History of Pa- 
per, complete Lists of Paper-Making Materials, List of American 
Machines, Tools and Processes used in treating the Raw Materials, 
and in Making, Coloring and Finishing Paper. By CHARLES T. 
Davis. Illustrated by 156 engravings. 608 pages, Svo. ^6.00 

DAVIS. — The Manufacture of Leather: 

Being a Description of all the Processes for the Tanning and Tawing 
with Bark, Extracts, Chrome and all Modern Tannages in General 
Use, and the Currying, Finishing and Dyeing of Every Kind of Leather; 
Including the Various Raw Materials, the Tools, Machines, and all 
Details of Importance Connected with an Intelligent and Profitable 
Prosecution of the Art, with Special Reference to the Best American 
Practice. To which are added Lists of American Patents ( 1884-1897) 
for Materials, Processes, Tools and Machines for Tanning, Currying, 
etc. By Charles Thomas Davis. Second Edition, Revised, and 
in great part Rewritten. Illustrated by 147 engravings and 14 Sam- 
ples of Quebracho Tanned and Aniline Dyed Leathers. 8vo, cloth, 
712 pages. Price $7- 50 

DAWIDOWSKY— BRANNT.— A Practical Treatise on the 

Raw Materials and Fabrication of Glue, Gelatine, Gelatine 

Veneers and Foils, Isinglass, Cements, Pastes, Mucilages, 

etc. : 

Eased upon Actual Experience. By F. Dawidowsky, Technical 

Chemist. Translated from the German, with extensive additions, 

including a description of the most Recent American Processes, by 

William T. Brannt, Graduate of the Royal Agricultural College 

of Eldena, Prussia. 35 Engravings. l2mo. . . . ^2.50 

DE GRAFF.— The Geometrical Stair-Builders' Guide : 

being a Plain Practical System of Hand-Railing, embracing all its 
necessary Details, and Geometrically Illustrated by twenty-two Steel 
Engravings; together with the use of the most approved pnnciplef 
of Practical Geometry. By SiMON De Graff, Architect. 4.1©, 

^2.00 



HENRY CAREY BAIRD & CO.'S CATALOGUE. n 

DE KONINCK— DIETZ.— A Practical Manual of Chemical 
Analysis and Assaying : 

As applied to the Manufacture of Iron from its Ores, and to Cast Iron, 

Wrought Iron, and Steel, as found in Commerce. By L. L. Db 

KONINCK, Dr. Sc, and E. Dietz, Engineer. Edited with Notes, by 

Robert Mallet, F. R. S., F. S. G., M. I. C. E., etc. American 

Edition, Edited with Notes and an Appendix on Iron Ores, by A. A. 

Fesquet, Chemist and Engineer. l2mo. . . . ^1.50 

DUNCAN.— Practical Surveyor's Guide: 

Containing the necessary information to make any person of com^ 
mon capacity, a finished land surveyor without the aid of a teacher 
By Andrew Duncan. Revised. 72 engravings, 214 pp. i2mo. $1.50 

DUPLAIS. — A Treatise on the Manufacture and Distillation 
of Alcoholic Liquors : 
Comprising Accurate and Complete Details in Regard to Alcohol 
from Wine, Molasses, Beets, Grain, Rice, Potatoes, Sorghum, Aspho- 
del, Fruits, etc. ; with the Distillation and Rectification of Brandy. 
Whiskey, Rum, Gin, Swiss Absinthe, etc., the Prepar?tion of Arc', 
matic Waters, Volatile Oils or Essences, Sugars, Syrups, Aromatic 
Tinctures, Liqueurs, Cordial Wines, Effervescing Wines, etc., the 
Ageing of Brandy and the improvement of Spirits, with Copioaa 
Directions and Tables for Testing and Reducing Spirituous Liquors, 
etc., etc= Translated and Edited from the French of MM. DuPLAlS, 
Aine et Jeune. By M. McKennie, M. D. To which are added the 
United States Internal Revenue Regulations for the Assessment and 
Collection of Taxes en Distilled Spirits. Illustrated by fourteen 
folding plates and several wood engravings. 743 pp. 8vo. ^12.50 

DUSSAUCE.— Practical Treatise on the Fabrication of Matches, 
Gun Cotton, and Fulminating Powder. 
By Professor H. Dussauce. i2mo. .... 

DYER AND COLOR-MAKER'S COMPANION: 

Containing upwards of two hundred Receipts for making Colors, on 
the most approved principles, for all tlie various styles and fabrics now 
in existence ; with the Scouring Process, and plain Directions for 
Preparing, Washing-off, and Finishing the Goods. i2mo. ;$l.OO 

EDWARDS. — A Catechism of the Marine Steam-Engine, 
For the use of Engineers, Firemen, and Mechanics. A Practical 
Work for Practical Men. By Emory Edwards, Mechanical Engi- 
neer. Illustrated by sixty-three Engravings, including examples of 
the most modern Engines. Third edition, thoroughly revised, with 
much additional matter. l2mo. 414 ]iages . . . ^2 00 

EDWARDS. — Modern American Locomotive Engines, 
Their Design, Construction and Management. By Emory Edwards. 
Illustrated i2mo ^2.00 

ED WARDS.— The American Steam Engineer : 

Theoretical and Practical, with examples of the latest and most ap- 
proved American practice in the design and construction of Steam 
Engines and Boilers. For the use of engineers, machinists, boiler- 
Bfvakers, and engineering students. By Emory Edwards. Fully 
illustrated, 419 pages. i2mo. • . . , I52.50 



12 HENRY CAREY BAIRD & CO.'S CATALOGUE. 

EDWARDS. — Modern American Marine Engines, Boilers, and 

Screw Propellers, 

Their Design and Construction. Showing the Present Praaice ot 

the most Eminent Engineers and Marine Engine Builders in the 

United States. Illustrated by 30 large and elaborate plates. 4to. ^5.00 

'EDWARDS.— The Practical Steam Engineer's Guide 

In the Design, Construction, and Management of American Stationary, 
Portable, and Steam Fire- Engines, Steam Pumps, Boilers, Injector^ 
Governors, Indicators, Pistons and Rings, Safety Valves and Steam 
Gauges. For the use of Engineers, Firemen, and Steam Users. By 
Emory Edwards. Illustrated by 119 engravings. 4.20 pages, 
i2mo. .......... ;g2 50 

EISSLER.— The Metallurgy of Gold : 

A Practical Treatise on the Metallurgical Treatment of Gold-Bear- 
ing Ores, including the Processes of Concentration and Chlorination, 
and the Assaying, Melting, and Refining of Gold. By M. ElSSLER. 

With 132 Illustrations. l2mo. $5.00 

EISSLER.— The Metallurgy of Silver: 

A Practical Treatise on the Amalgamation, Roasting, and Lixiviation 
of Silver Ores, including the Assaying, Melting, and Refining of 
Silver Bullion. By M. Eissler. 124 Illustrations. 336 pp. 
i2mo. .......... $425 

ELDER. — Conversations on the Principal Subjects of Political 
Economy. 
By Dr. William Elder. 8vo ^2 50 

ELDER.— Questions of the Day, 

Economic and Social. By Dr. William Elder. 8vo. . ^3.00 

ERNI. — Mineralogy Simplified. 

Easy Methods of Determining and Classifying Minerals, including 
Ores, by means of the Blowpipe, and by Humid Chemical Analysis, 
based on Professor von Kobell's Tables for the Determination of 
Minerals, with an Introduction to Modern Chemistry. By Henry 
Erni, A.M., M.D., Professor of Chemistry. Second Edition, rewritten, 
enlarged and improved. i2mo. ..... 

FAIRBAIRN.— The Prmciples of Mechanism and Machinery 
of Transmission • 
Comprising the Prmciples of Mechanism, Wheels, and Pulleys, 
Strength and Proportionsof Shafts, Coupling of Shafts, and Engag- 
ing and Disengaging Gear. By SiR WiLLlAM Fairbairn, Bart 
C. E. Beautifully Illustrated by over 150 wood-cuts. In one 
volume, i2mo ......*•• ^2.00 

FLEMING.— Narrow Gauge Railways in America. 
A Sketch of their Rise, Progress, and Success. Valuable Statistics 
as to Grades, Curves, Weight of Rail, Locomotives, Cars, etc. By 
Howard Fleming. Illustrated, 8vo ;^i 00 

FORSYTH.— Book of Designs for Headstones, Mural, and 
other Monuments : 
Containing 78 Designs. By James Forsyth. With an Introduction 
by Charles Boutell, M. A. 4 to., cloth . . • $3-5^ 



HENRY CAREY BAIRD & CO.'S CATALOGUE. ^3 



■PRANKEL— HUTTER.— A Practical Treatise on the Manu* 
facture of Starch, Glucose, Starch-Sugar, and Dextrine: 
Based on the German of Ladislaus Von Wagner, Professor in the 
Royal Technical High School, Buda-Pest, Hungary, and other 
authorities. By Julius Frankkl, Graduate of the Polytechnic 
School of Hanover. Edited by Robert Hutter, Chemist, Practical 
Manufacturer of Starch-Sugar. Illustrated by 58 engravings, cover- 
ing every branch of the sui^ject, including examples of the most 
Recent and Best American Machinery. 8vo., 344 pp. . $3 50 

GARDNER.— The Painter's Encyclopaedia: 
Containing Definitions of a'.l Important Words in the Art of Plain 
and Artistic Painting, with Details of Piactice in Coach, Carriage, 
Railway Car, House, Sign, and Ornamental Painting, including 
Graining, Marbling, Staining, Varnishing, Polishing, Lettering, 
Stenciling, Gilding, Bronzing, etc. By P^ranklin B. Gardner. 
158 Illustrations. i2mo. 427 pp. ..... $2.oa 

GARDNER.— Everybody's Paint Book: 

A Complete Guide to the Art of Outdoor and Indoor Painting, De- 
signed for the Special Use of those who wish to do their own work, 
and consisting of Practical Lessons in Plain Painting, Varnishing, 
Polishing, Staining, Fa'Dcr Hanging, Kalsomining, etc., as well as 
Directions for Renovating Furniture, and Hints on Artistic Work for 
Home Decoration. 38 Illustrations. I2mc., 183 pp. . ^I.oo 

GEE. — The Goldsmith's Handbook : 

Containing full instructions for the Alloying and Working of Gold, 
including the Art of Alloying, Melting, Reducing, Coloring, Col- 
lecting, and Refining; the Processes of Manipulation, Recovery of 
Waste; Chemical and Physical Properties of Gold; with a New 
System of Mi.<ing its Alloys ; Solders, Enamels, and other Useful 
Rules and Recipes. By George E. Gee. i2mo. ^ . i?l.25 

GEE.— The Silversmith's Handbook : 

Containing full instructions for the Alloying and Working of Silver, 
including the different modes of Refinir-^ :ind Melting the Metal ; its 
Solders; the Preparation of Imitation Alloys; Methods of Manipula- 
tion ; Prevention of Waste ; Instructions for Improving and Finishing 
the Surface of the Work ; together with other Useful Information and 
Memoranda. By George E. Gee. Illustrated. i2mo. Si. 25 

GOTHIC ALBUM FOR CABINET-MAKERS: 

Designs for Gothic Furniture. Twenty-three plates. Oblong $1-$'^ 

jRANT. — A Handbook on the Teeth of Gears : 
Their Curves, Properties, and Practical Construction. By Georgb 
B. Grant. Illustrated. Third Edition, enlarged. 8vo. $1 00 

GREENWOOD.- Steel and Iron: 

Comprising the Practice and Theory of the Several Methods Pur- 
sued in their Manufacture, and of their Treatment in the Rolling- 
Mills, the Forge, and the Foundry. By William Henry Green- 
wood, F. C. S. With 97 Diagrams, 536 pages. i2mo. ;$2.oo 



14 HENRY CAREY BAIRD & CO.'S CATALOGUE. 



GREGORY, — Mathematics for Practical Men : 

Adapted to the Pursuits of Surveyors, Architects, Mechanics, and 
Civil Engineers. By Olinthus Gregory. 8vo., plates $3.00 

ORIS WOLD. — Railroad Engineer's Pocket Companion for the 
Field : 
Comprising Rules for Calculating Deflection Distances and Angles, 
Tangential Distances and Angles, and all Necessary Tables for En 
gineers; also the Art of Levelling from Preliminary Survey to the 
Construction of Railroads, intended Expressly for the Young En- 
gineer, together with Numerous Valuable Rules and Examples. By 
W. Griswold. i2mo., tucks iJl-SO 

GRUNER. — Studies of Blast Furnace Phenomena: 

By M. L. Gruner, President of the General Council of Mines oi 
France, and lately Professor of Metallurgy at the Ecole des Mines. 
Translated, with the author's sanction, with an appendix, by L. D. 
B. Gordon, F. R. S. E., F. G. S. 8vo. . . . $2.50 

Hand-Book of Useful Tables for the Lumberman, Farmer and 
Mechanic: 
Containing Accurate Tables of Logs Reduced to Inch Board Meas. 
ure. Plank, Scantling and Timber Measure ; Wages and Rent, by 
Week or Month; Capacity of Granaries, Bins and Cisterns; Land 
Measure, Interest Tables, with Directions for Finding the Interest on 
any sum at 4, 5, 6, 7 and 8 per cent., and many other Useful Tables. 
32 mo., boards. 186 pages .25 

HASERICK.— The Secrets of the Art of Dyeing Wool, Cotton, 
and Linen, 
Including Bleachlrg and Coloring Wool and Cotton Hosiery and 
Random Yarns. A Treatise based on Economy and Practice. By 
E. C. Haserick. Illustrated by 323 Dyed Fatte}-ns of the Yarm 
or Fabrics. 8vo. ........ ^7-50 

HATS AND FELTING: 

A Practical Treatise on their Manufacture. By a Practical Hatter, 
Illustrated by Drawings of Machinery, etc. 8vo. . . ^1.2$ 

HOFFER. — A Practical Treatise on Caoutchouc and Gutta 
Percha, 
Comprising the Properties of the Raw Materials, and the manner or 
Mixing and Working them ; with the Fabrication of Vulcanized and 
Hard Rubbers, Caoutchouc and Gutta Peucha Compositions, Water- 
proof Substances, Elastic Tilssues, the Utilization of Waste, etc., cic, 
From ihe German of Raimund Hoffer, By W, T. Erannt. 
Illustrated i2mo I2.5C 

HAUPT.— Street Railway Motors: 

With Descriptions and Cost of Plants and Operation of the Variouj 
Systems now in Use. i2mo. . . , , . i?i-75 



HENRY CAREY BAIRD & CO.'S CATALOGUE, 15 



HAUPT— RHAWN.— A Move for Better Roads: 

Essays on Road-making and Maintenance and Road Laws, for 
which Prizes or Honorable Mention were Awarded through the 
University of Pennsylvania by a Committee of Citizens of Philadel- 
phia, with a Synopsis of other Contributions and a Review by the 
Secretary, Lewis M. Haupt, A. M., C. E.; also an Introduction by 
William H. Rhawn, Chairman of the Committee. 319 pages. 



8vo. 



;^2.oo 



HUGHES, — American Miller and Millwright's Assistant; 

By William Carter Hughes. i2mo ^1.50 

HULME.— Worked Examination Questions in Plane Geomet- 
rical Drawing : 

For the Use of Candidates for the Royal Military Academy, Wool- 
wich; the Royal Military College, Sandhurst ; the Indian Civil Ei- 
gineenng College, Cooper's Hill ; Indian Public Works and Tele- 
graph Departments ; Royal Marine Light Infantry; the Oxford and 
Cambridge Local Examinations, etc. By F. Edward Hulme, F. L. 
S., F. S. A., Art-Master Marlborough College, Illustrated by •300 
examples. Small quarto «2 ca 

JERVIS.— Railroad Property: * * * ' # O^ 

A Treatise on the Construction and Management of Railways; 
designed to afford useful knowledge, in the popular style, to the 
holders of this class of property ; as well as Railway Managers, Offi- 
cers, and Agents. By John B. Jervis, late Civil Engineer of the 
Hudson River Railroad, Croton Aqueduct, etc. i2mo., cloth ^2.oc 

KEENE. — A Hand-Book of Practical Gauging: 

For the Use of Beginners, to which is added a Chapter on Distilla- 
tion, describing the process in operation at the Custom-House for 
ascertaining the Strength of Wines. By James B. Keene, of H. M. 
Customs. 8vo. ........ ^i.oo 

KELLEY. — Speeches, Addresses, and Letters on Industrial and 
Financial Questions : 
By Hon. William D. Kelley, M. C. 544 pages, 8vo, , £2,50 

KELLOGG, — A New Monetary System : 

The only means of Securing the respective Rights of Labor and 
Properly, and of Protecting the Public from Financial Revulsions. 
By Edward Kellogg, Revised from his work on "Labor and 
other Capital." With numerous additions from his mnnuscript. 
Edited by MARY Kellogg Putnam, Fifth edition. To which ie 
added a Biographical Sketch of the Author. One volume, izmo. 

Paper cover |l.oo 

Bound in cloth ..,.,.,. 1.2c 

KEMLO,— Watch-Repairer's Hand-Book: 
Being a Complete Guide to the Young Beginner, in Taking Apart, 
Putting Together, and Thoroughly Cleaning the English Lever and 
other Foreign Watches, and all American Watches. By F, Kemlo, 
Practical Watchmaker, With Illustrations, i2mo, . i^l-25 



l6 HENRY CAREY BAIRD & CO.'S CATALOGUE. 

KENTISH.— A Treatise on a Box of Instruments, 

And the Slide Rule ; with the Theory of Trigonometry and Loga 
rithms, including Practical Geometry, Surveying, Measuring of Tim 
ber, Cask and Malt Gauging, Heights, and Distances. By Thoma'^ 
Kentish. In one volume. i2mo. .... $i.oo 

KERL. — The Assayer's Manual: 

An Abridged Treatise on the Docimastic Examination of Ores, and 
Furnace and other .Artificiil Products. By Bruno Kerl, Professor 
in the Royal School of Mines. Translated from the German hy 
William T. Brannt. Second American edition, edited with Ex- 
tensive Additions by F. Lynwood Garrison, Member of the 
American Institute of Mining Engineers, etc. Illustrated by 87 en- 
gravings. 8vo $3.0C 

KICK.— Flour Manufacture. 
A Treatise on Milling Science and Practice. By Frederick Kick 
Imperial Regierungsrnth, Professor of Mechanical Technology in tht 
imperial German Polytechnic Institute, Prague. Translnted from 
the second enlarged and revised edition with supplement by H. H. 
P. PoWLES, Assoc. Menib Institution of Civil Engineers. Illustrated 
with 28 Plat<?.s, and 167 Wood-cuts. 367 pages. 8vo. . ^lo.OO 
KINGZETT.— The History, Products, and Processes of the 
Alkali Trade : 
Including the most Recent Improvements. By Charles Thomasj 
KiNGZETT, Consulting Chemist. With 23 illustrations. 8vo. ^^2.50 
LANDRIN.— A Treatise on Steel : 

Comprising its Theory, Metallurgy, Properties, Practical Working, 
and Use. By M. H. C. Landrin, Jr. I^rom tlie French, by A. A. 

Fesquet. i2mo . . ^2.50 

LANGBEIN. — A Complete Treatise on the Electro-Deposi- 
tion of Metals : 
Comprising Electro-Plating and Galvanoplastic Oper.Ttions, the De- 
position of Metals by the Contact and Immersion Processes, tlie Color- 
ing of Metals, the Methods of Grinding and Polishing, as well as 
Descriptions of the Electric Elements. Dynamo-Eleclric Maciiines, 
Thermo-Piles and of the Materials and Processes used in Every De- 
partment of the Art. From the German of Dr. George Langbein, 
with additions by Wm. T. Brannt. Third Edition, thoroughly re- 
vised and much enlarged. 150 Engravings. 520pages. 8vo. ^4.00 

LARDNER.— The Steam-Engine : 

Foi* the Use of Beginners. Illustrated. i2mo. • • • 73 
•-EHNER.— The Manufacture of Ink: 

Comprising the Raw Materials, and the Preparation df Waiting, 
Copying and Hektograph Inks, Safety Inks, Ink Extracts and Pow- 
ders, etc. Translated from the German of SiGMUND Lehner, with 
additions by William T. Brannt. Illustrated. i2mo. $2:(k> 



HENRY CAREV BAIRD & CO.'S CATALOGUE. 17 

LARKIN. — The Praciicai Brass and Iron Founder's Guide: 
A Concise Treatise on Brass Founding, Moulding, the Metals and 
their Alloys, etc. ; to which are added Recent Improvements in th« 
Manufacture of Iron, Steel by the Bessemer Process, etc., etc. By 
James Larkin, late Conductor of the Brass Foundry Department ia 
keany, Neafie & Co.'s Penn Works, Philadelphia. New edition, 
revised, with extensive additions. l2mo. . . . $2.53 

LEROUX. — A Practical Treatise on the Manufacture of 
Worsteds and Carded Yarns : 
Comprising Practical Mechanics, with Rules and Calculations applied 
to Spinning; Sorting, Cleaning, and Scouring Wools; the English 
and French Methods of Combing, Drawing, and Spinning Worsteds, 
and Manufacturing Carded Yarns. Translated from the French of 
Charles Leroux, Mechanical Engineer and Superintendent of a 
Spinning-Mill, by Horatio Paine, M. D., and A. A. Fesquet, 
Chemist and Engineer. Illustrated by twelve large Plates. To which 
is added an Appendix, containing Extracts from the Reports of the 
International Jury, and of the Artisans selected by the Committee 
appointed by the Council of the Society of Arts, London, on Woolen 
and Worsted Machinery and Fabrics, as exhibited in the Paris Uni» 
versal Exposition, 1867. 8vo. ..... ^5.00 

LEFFEL. — The Constructicn of Mill-Dams : 
Comprising also the Building of Race and Reservoir Embankments 
and Head-Gates, the Measurement of Streams, Gauging of Water 
Supply, etc. By James Leffel & Co. Illustrated by 58 engravings. 
8vo. ^2.50 

LESLIE.— Complete Cookery: 
Directions for Cookery in its Various Branches. By Miss Leslie. 
Sixtieth thoHsand. Thoroughly revised, with the addition of New 
Receipts. i2mo $^-S° 

LE VAN. — The Steam Engine and the Indicator : 

Their Origin and Progressive Development ; including the Most 
Recent Examples of Steam and Gas Motors, together with the Indi- 
cator, its Principles, its Utility, and its Application. By William 
Barnet Le Van. Illustrated by 205 Engravings, chiefly of Indi- 
cator-Cards. 469 pp. 8vo. ...... ^4.00 

LIEBER.— Assayer's Guide : 
Or, Practical Directions to Assayers, Miners, and Smelters, for the 
Tests and Assays, by Heat and by Wet Processes, for the Ores of all 
the principal Metals, of Gold and Silver Coins and Alloys, and of 
Coal, etc. By Oscar M. LiEBER. Revised. 283 pp. i2mo. ^1.50 

IrOckwood's Dictionary of Terms : 

Used in the Practice of Mechanical Engineering, embracing those 
Current in the Drawing Office, Pattern Shop, Foundry, Fitting, Turn- 
ing, Smith's and Boiler Shops, etc., etc., comprising upwards of Six' 
Thousand Definitions. Edited by a Foreman Pattern Maker, author 
of " Pattern Making." 417 pp. l2mo. . . . ^^J-OO 



i8 HENRY CAREY BAIRD & CO.'S CATALOGUE. 

LUKIN.— Amongst Machines: 
Embracing Descriptions of the various Mechanical Appliances used 
in the Manufacture of Wood, Metal, and other Substances. l2mo. 

LUKIN.— The Boy Engineers: 

What They Did, and How They Did It. With 30 plates. l8mo. 

LUKIN.— The Young Mechanic c 

Practical Carpentry. Containing Directions for the Use of all kinds 
of Tools, and for Construction of Steam- Engines and Mechanical 
Models, including the Art of Turning in Wood and Metal. By John 
LUKlN, Author of "The Lathe and Us Uses," etc. Illustrated. 
l2mo $i.7S 

MAIN and BROWN. — Questions on Subjects Connected with 

the Marine Steam-Engine: 

And Examination Papers; with Hints for their Solution. By 

Thomas J. Main, Professor of Mathematics, Royal '^"laval College, 

and Thomas Bfiown, Chief Engineer, R. N. i2mo., cloth . ^i.oo 

MAIN and BROWN. — The Indicator and Dynamometer: 
With their Practical Applications to the Steam-Engine. By THOMAS 
J. Main, M. A. F. R., Ass't S. Professor Royal Naval College, 
Portsmouth, and THOMAS Brown, Assoc. Inst. C. E., Chief Engineer 
R. N., attached to the R. N. College. Illustrated. Svo. . 

MAIN and BROWN.— The Marine Steam-Engine. 
By Thomas J. Main, F. R. Ass't S. Mathematical Professor at the 
Royal Naval College, Portsmouth, and Thomas Brown, Assoc. 
Inst. C. E., Chief Engineer R. N. Attached to the Royal Naval 
College. With numerous illustrations. Svo. 

MAKINS.— A Manual of Metallurgy: 

By George Hogarih Makins. 100 engravings. Second edition 
rewritten and much enlarged. i2mo., 592 pages . . $3-oo 

MARTIN.— Screw-Cutting Tables, for the Use of Mechanicai 
Engineers : 
Showing the Proper Arrangement of Wheels for Cutting the Threads 
of Screws of any Required Pitch ; with a Table for Making the Uni- 
versal Gas-Pipe Thread and Taps. By W. A. Martin, Engineer. 
Svo. . .50 

MICHELL.— Mine Drainage: 
Being a Complete and Practical Treatise on Direct-Acting Under- 
ground Steam Pumping Machinery. With a Description of a large 
number of the best known Engines, their General Utility and the 
Special Sphere of their Action, the Mode of their Application, and 
their Merits compared with other Pumping Machinery. By STEPHEN 
Michell. Illustrated by 137 engravings. Svo., 277 pages . ^6.00 

MOLESWORTH.— Pocket-Book of Useful Formulae and 

Memoranda for Civil and Mechanical Engineers. 

By Guilford L. Molesworth, Member of the Institution of Civil 

Engineers, Chief Resident Engineer of the Ceylon Railway. FuU- 

buund in Pocket-book form ...••< Ji^i.oo 



HENRY CAREY BAIRD & CO.'S CATALOGUE. 19 

MOORB. — The Universal Assistant and the Complete Me- 
chanic : 

Containing over one million Industrial Facts, Calculations, ReceiptSJ- 
Processes, Trades Secrets, Rules, Business Forms, Legal Items, Etc.,- 
in every occupation, from tiie Houseliold to the Manufactory. By- 
R. Moore. Illustrated by 500 Engravings. i2mo. . $2..ys' 

MORRIS. — Easy Rules for the Measurement of Earthworks: 
By means of tiie Prismoidal Formula. Illustrated with NumerouS- 
Wood-Cuts, Problems, and Examples, and concluded by an Exteav 
sive Table for finding the Solidity in cubic yards from Mean Areas. 
The whole being adapted for convenient use by Engineers, Surveyors, 
Contractors, and others needing Correct Measurements of Earthwork. 

By Elwood Morris, C. E. 8vo 5 1.50 

MAUCHLINE.— The Mine Foreman's Hand-Book 

Of Practical and Theoretical Information on the Opening, Venti- 
lating, and Working of Collieries. Questions and Answers on Prac- 
tical and Theoretical Coal Mining. Designed to Assist Students and 
Others in Passing Examinations for Mine Foremanships. By 
Robert Mauchline, Ex-Inspector of Mines. A New, Revised and 
Enlarged Edition. Illustrated by 1 14 engravings. 8vo. 337 

pages I3.75 

NAPIER. — A System of Chemistry Applied to Dyeing. 

By James Napier, F. C. S. A New and Thoroughly Revised Edi- 
tion. Completely brought up to the present state of the Science, 
including the Chemistry of Coal Tar Colors, by A. A. Fesquet, 
Chemist and Engineer. With an Appendix on Dyeing and Calica 
Printing, as shown at the Universal Exposition, Paris, 1867. Illus- 
trated. 8vo. 422 pages ^3.oO' 

NEVILLE.— Hydraulic Tables, Coefficients, and Formula, foi 
finding the Discharge of Water from Orifices, Notches, 
Weirs, Pipes, and Rivers: 
Third Edition, with Additions, consisting of New Formulae for the 
Discharge from Tidal and Flood Sluices and Siphons; general infor 
mation on Rainfall, Catchment-Basins, Drainage, Sewerage, Water 
Supply for Towns and Mill Power. By Tohn Neville. C. E. M R 
I. A. ; Fellow of the Royal Geological Society of Ireland. Thick 

I2mo $5.50 

lUEWBERY.— Gleanings from Ornamental Art of every 
style : 
Drawn from Examples in the British, South Kensington, Indian, 
Crystal Palace, and other Museums, the Exhibitions of 185 1 and 
1862, and the best English and Foreign works. In a series of loa 
exquisitely drawn Plates, containing many hundred examples. By 

Robert Newbery. 4to. ^12.50 

NICHOLLS.— The Theoretical and Practical Boiler- M aker an(f 
Engineer's Reference Book: 
Containing a variety of Useful Information for Employers of Labot 
Foremen and Working Boiler-Makers. Iroo, Copper, and Tinsmith* 



20 HENRY CAREY BAIRD & CO.'S CATALOGUE. 



Draughtsmen, Engineers, the General Steam-using Public, and for the 
Use of Science Schools and Classes. By SAMUEL NiCHOLLS. lUu^ 
trated by sixteen plates, i2mo. ..... ^^2.50 

NICHOLSON.— A Manual of the Art of Bookbinding : 

Containing full instructions in the different Branches of Forwarding, 
Gilding, and Finishini^. Also, the Art of Marbling Book-edges and 
Paper. By James B. NICHOLSON. Illustrated. i2mo., cloth ^2.25 

NICOLLS.— The Railway Builder: 

A Hand-Book for Estimating the Probable Cost of American Ra.U 
way Construction and Equipment. By WiLLlAM J. NiCOLLS, Civil 
Engineer. Illustrated, full bound, pocket-book form 

NORMANDY. — The Commercial Handbook of Chemical An- 
alysis : 
Or Practical Instructions for the Determination of the Intrinsic oi 
Commercial Value of Substances used in Manufactures, in Trades, 
and in the Arts. By A. Normandy. New Edition, Enlarged, and 
to a great extent rewritten. By Henry M. Noad, Ph.D., F.R.S., 
thick i2mo $S.oc 

NORRIS. — A Handbook fcr Locomotive Engineers and Ma- 
chinists : 
Comprising the Proportions and Calculations for Constructing Loco- 
motives; Manner of Setting Valves; Tables of Squares, Cubes, Areas, 
etc., etc. By Septimus Norris, M. E. New edition. Illustrated, 
I2mo $1.50 

NYSTROM. — A New Treatise on Elements of Mechanics : 
Establishing Strict Precision in the Meaning of Dynamical Terms : 
accoirpanied with an Appendix on Duodenal Arithmetic and Me 
trologv. By John W. Nystrom, C. E. Illustrated. 8vo. $3.00 

NYSTROM^— On Technological Education and the Construc- 
tion of Ships and Screw Propellers : 
For Naval and Marine Engineers. By John W. Nystrom, late 
Acting Chief Engineer, U. S. N. Second edition, revised, with addi- 
tional matter. Illustrated by seven engravings. i2mo. . ^1-25 

O'NEILL. — A Dictionary of Dyeing and Calico Printing: 

Containing a brief account of all the Substances and Processes in 
use in the Art of Dyeing and Printing Textile Fabrics ; with Practical 
Receipts and Scientific Information. By Charles O'Neill, Analy- 
tical Chemist. To which is added an Essay on Coal Tar Colors and 
their application to Dyeing and Calico Printing. By A. A. Fesquet, 
Chemist and Engineer. With an appendix on Dyeing and Calico 
Printing, as shown at the Universal Exposition, Paris, 1867- 8vo., 
491 pages ^3.00 

ORTON. — Underground Treasures-. 

How and Where to Find Them. A Key for the Ready Determination 
of all the Useful Minerals within the United States. By James 
OrTON, A.m., Late Professor of Natural History in Vassar College, 
A3. Y.; Cor. Mem. of the Academy of Natural Sciences, Philadelpiiia, 
and of the Lyceum of Natural History, New York ; author of the 
'•Andes and the Amazon," etc. A New Edition, with Additions. 
Ulustrated ^(1.59 



HENRY CAREY BAIRD & CO.'S CATALOGUE. 21 

OSBORN.— The Prospector's Field Book and Guide. 

In the Search For and the Easy Determination of Ores and Other 
Useful Minerals. By Prof. H. S. OsBORN, LL. D. Illustrated by 58 
Engravings. l2mo. Third Edition. Revised and Enlarged (1897). 

^1.50 
OSBORN — A Practical Manual of Minerals, Mines and Min- 
ing : 
Comprising the Physical Properties, Geologic Positions, Local Occur- 
rence and Associations of the Useful Minerals ; their Methods of 
Chemical Analysis and Assay ; together with Various Systems of Ex- 
cavating and Timbering, Brick and Masonry Work, during Driving, 
Lining, Bracing and other Operations, etc. By Prof. H. S. OsBORN, 
LL. D., Author of " The Prospector's Field- Book and Guide." 171 
engravings. Second Edition, revised. 8vo. • . . M>50 
OVERMAN.— The Manufacture of Steel : 

Containing the Practice and Principles of Working and Making Steel. 
A Handbook for Blacksmiths and Workers in Steel and Iron, Wagon 
Makers, Die Sinkers, Cutlers, and Manufacturers of Files and Hard- 
ware, of Steel and Iron, and for Men of Science and Art. By 
Frederick Overman, Mining Engineer, Author of the " Manu- 
facture of Iion," etc. A new, enlarged, and revised Edition. By 
A. A. Fesqi^iST, Chemist and Engineer. i2mo. . . ^1.50 
OVERMAN. —The Moulder's and Founder's Pocket Guide : 
A Treatise orj Moulding and F'ounding in Green-sand, Drysand,Loam, 
and Cement; the Moulding of Machine Frames, Mill-gear, Hollow- 
ware, Ornamerts, Trinkets, Bells, and Statues; Description of Moulds 
for Iron, Brcnze, Brass, and other Metals; Plaster of Paris, Sulphur, 
Wax, etc. ; the Construction of Melting Furnaces, the Melting and 
Founding of Metals ; the Composition of Alloys and their Nature, 
etc., etc. By Frederick Overman, M. E. A new Edition, to 
which is added a Supplement on Statuary and Ornamental Moulding, 
Ordnance, Malleable Iron Castings, etc. By A. A. Fesquet, Chem- 
ist and Engineer. Illustrated by 44 engravings. l2mo. . $2.O0 
PAINTER, GILDER, AND VARNISHER'S COMPANION. 
Comprising the Manufacture and Test of Pigments, the Arts of Paint- 
ing, Graining, Marbling, Staining, Sign- writing. Varnishing, Glass- 
staining, and Gilding on Glass; together with Coach Painting and 
Varnishing, and tlie Principles of the Harmony and Contrast of 
Colors. Twenty-seventh Edition. Revised, Enlarged, and in great 
part Rewritten. By William T. Brannt, Editor of " Varnishes, 
Lacquers, Printing Inks and Sealing Waxes." I Illustrated. 395 pp. 

l2mo ^I 50 

PALLETT. — The Miller's, Millwright's, and Engineer's Guide. 
Bv Henry Pallett. Illustrated. i2mo. . . . ^2.00 



22 HENRY CAREY BAIRD & CO.'S CATALOGUE. 

PERCY. — The Manufacture of Russian Sheet-Iron. 

By John Percy, M. D., F. R. S., Lecturer on Metallurgy at the 
Royal School of Mines, and to The Advance Class of Artillerj 
Officers at the Royal Artillery Institution, Woolwich; Author of 
" Metallurgy." With Illustrations. 8vo., paper . . 25 cts. 

PERKINS.— Gas and Ventilation : 

Practical Treatise on Gas and Ventilation. With Special Relation 
to Illuminating, Heating, and Cooking by Gas. Including ScientiSic 
Helps to Engineer-students and others. With Illustrated Diagrams. 

By E. E. Perkins. i2mo., cloth $1.25 

t*ERKINS AND STOWE.— A New Guide to the Sheet-iron 
and Boiler Plate Roller : 
Containing a Series of Tables showing the Weight of Slabs and Piles 
to Produce Boiler Plates, and of the Weight of Piles and the Sizes of 
Bars to produce Sheet-iron ; the Thickness of the Bar Gauge 
in decimals ; the Weight per foot, and the Thickness on the Bar or 
Wire Gauge of the fractional parts of an inch; the Weight per 
sheet, and the Thickness on the Wire Gauge of Sheet-iron of various 
dimensions to weigh 112 lbs. per bundle; and the conversion of 
Short Weight into Long Weight, and Long Weight into Short. 
Estimated and collected by G. H. Perkins and J. G. Stowe. ^1.50 

POWELL— CHANCE— HARRIS.— The Principles of Glass 

Making. 

By Harry J. Powell, B. A. Together with Treatises on Crown and 

Sheet Glass; by Henry Chance, M. A. And Plate Glass, by H. 

G. Harris, Asso. M. Inst. C. E. Illustrated i8mo. . ^1.50 

PROCTOR.— A Pocket-Book of Useful Tables and Formulae 
for Marine Engineers : 
By Frank Proctor. Second Edition, Revised and Enlarged. 
Full -bound pocket-book form . . . . . . $1.50 

REGNAULT.— Elements of Chemistry: 

By M. V. Regnault. Translated from the French by T. FoRREST 
Betton, M. D., and edited, with Notes, by James C. Booth, Meiter 
and Refiner U. S. Mint, and William L. Faber, Metallurgist and 
Mining Engineer. Illustrated by nearly 700 wood-engravings. Com- 
prising nearly 1,500 pages. In two volumes, 8vo., cloth . $6.00 

RICHARDS.— Aluminium : 

Its History, Occurrence, Properties, Metallurgy and Applications, 
including its Alloys. By Joseph W. Richards, A. C, Chemist and 
Practical Metallurgist, Member of the Deutsche Chemische Gesell- 
schaft. Illust. Third edition, enlarged and revised (1895) . ^6.00 

RIFFAULT, VERGNAUD, and TOUSSAINT.— A Practical 
Treatise on the Manufacture of Colors for Painting: 
Comprising the Origin, Definition, and Classification of Colors; the 
Treatment of the Raw Materials ; the best Formulae and the Newest 
Processes for the Preparation of every description of Pigment, and 
the Necessary Apparatus and Directions for its Use ; Dryers ; the 
Testing. Application, and Qualities of Paints, etc., etc. By MM. 
RiFFAULT, Vergnaud, and ToussAlNT. Revised and Edited by M. 



HENRY CAREY BAIRD & CO.'S CATALOGUE. 23 

F. Malepeyre. Translated from the French, by A. A. FESQT)rw> 
Chemist and Engineer. Illustrated by Eighty engravings. In one 
vol., 8vo., 659 pages ^5-00 

ROPER. — A Catechism of High-Pressure, or Non-Condensing 
Steam-Engines : 

Including tlie Modelling, Constructing, and Management of Steam- 
P^ngines and Steam Boilers. With valuable illustrations. By Ste- 
phen Roper, Engineer. Sixteenth edition, revised and enlarged. 
1 8mo., tucks, gilt edge ....... $2.00 

ROPER.— Engineer's Handy-Book: 

Containing a full Explanation of the Steam-Engine Indicator, and its 
Use and Advantages to Engineers and Steam Users. With Formulae 
for Estimating the Power of all Classes of Steam-Engines; alsu. 
Facts, Figures, Questions, and Tallies for Engineers vv'ho wish to 
qualify themselves ior the United Stales Navy, the Revenue Service, 
the Mercantile Marine, or to take charge of the Better Class of Sta- 
tionary Steam-Engines. Sixth edition. i6mo.. 690 pagts, tucks, 
gilt edge ^3.50 

ROPER. — Hand-Book of Land and Marine Engines ; 
Including tlie Modelling, Construction, Running, and Management 
of Land and Marine Engines and Boilers. With il'ustrations. By 
Stephen Roper, Engineer. Sixth edition. i2mo.,ti'clts, gilt edge. 

^3-50 
ROPER.— Hand-Book of th6 Locomotive : 

Including the Construction of Engines and Boders, and the Construc- 
tion, Management, and Running of Locomotives. By STEPHEN 
RoPER. Eleventh edition. iSmo., tucks, gilt edge . ^2.50 

ROPER. — Hand-Book of Modern Steam Fi-e-Engines. 

With illustrations. By Stephen Roper, Engineer. Fourth edition, 
i2mo., tucks, gilt edije ....... ^3.50 

ROPER. — Questions and Answers for Engineers. 

This little book contains all the Questions that Engineers will be 
asked when undergoing an Examination for the purpose of procuring 
Licenses, and they are so plain that any Engineer or Fireman of or 
dinary intelligence may commit them to memory in a short time.. By 
Stephen Roper, Ent;ineer. Third edition . . . ^2.00 
ROPER. — Use and Abuse of the Steam Boiler. 
By Stephen Roper, Engineer. Eighth edition, with illustrations. 
l8mo., tucks, gilt edge ....... j^2.00 

ROSE. — The Complete Practical Machinist : 

Embracing Lathe Work, Vise Work, Drills and Drilling, Taps and 
Dies, Hardening and Tempering, the Making and Use of Tools. 
Tool Grinding, Marking out Work, Macliine Tools, etc. By JoSHUA 
Rose. 39s Engravings. Nineteenth Edition, greatly Enlarged with 
New an(l Valuable Matter. i2mo., 504 pages. . . ^2.50 

ROSE. — Mechanical Drawing Self-Taught : 

Comprising Instructions in the Selection and Preparation of Drawing 
Instruments, Elementary Instruction in Practical Mechanical Draw- 



24 HENRY CAREY BAIRD & CO.'S CATALOGUE. 

■ ' — — ' \ 

ing, together with Examples in Simple Geometry and Elementary 
Mechanism, including Screw Threads, Gear Wheels, Mechanical 
Motions, Engines and Boilers. By JosHUA Rose, M, E. Illustrated 
by 330 engravings. 8vo., 313 pages .... ^4.00 

ROSE.— The Slide- Valve Practically Explained: 

Embracing simple and complete Practical Demonstrations of thk 
operation of each element in a Slide-valve Movement, and illustrate 
ing the effects of Variations in their Proportions by examples care- 
fully selected from the most recent and successful practice. By 
Joshua Rose, M. E. Illustrated by 35 engravings . ;{Si.oo 

ROSS. — The Blowpipe in Chemistry, Mineralogy and Geology: 

Containing all Known Methods of Anhydrous Analysis, many Work- 
ing Examples, and Instructions for Making Apparatus. By Lieut.- 
Colonel W. A. Ross, R. A., F. G. S. With 120 Illustrations. 
i2mo. .......... ;$l2.oo 

SHAW.— Civil Architecture : 

Being a Complete Theoretical and Practical System of Building, con- 
taining the Fundamental Principles of the Art. By Edward Shaw, 
Architect. To which is added a Treatise on Gothic Architecture, etc. 
By Thomas W. Silloway and George M. Harding, Architects. 
The whole illustrated by 102 quarto plates finely engraved on copper. 
Eleventh edition. 4to. ....... $6.00 

SHUNK. — A Practical Treatise on Railway Curves and Loca- 
tion, for Young Engineers. 

By W. F. Shunk, C. E. i2mo. J uU bound pocket-book form ^2.00 
SLATER. — The Manual of Colors and Dye Wares. 

By J. W. Slater. i2mo ^3.00 

SLOAN. — American Houses: 

A variety of Original Designs for Rural Buildings. Illustrated by 
26 colored engravings, with descriptive references. By Samuel 
Sloan, Architect. 8vo. ^I.oo 

SLOAN. — Homestead Architecture: 

Containing Forty Designs for Villas, Cottages, and Farm-houses, with 
Essays on Style, Construction, Landscape Gardening, Furniture, etc., 
etc. Illustrated by upwards of 200 engravings. By Samuel Sloan, 
Architect. 8vo. ..-,.... $3-00 

SLOANE. — HoiTe Experiments iii Science. 

By T. O'CoNOR Slcane, E. M., A. M., Fh. D. Illustrated by 91 
engravings. i2mo. ....... ^I.oo 

SMEATON.— Builder's Pocktl-Companion : 

Containing the Elements of Building, -Surveying, and Architecture; 

with Practical Rules and Instructions connected with the subject. 

By A. C. Smeaton, Civil Engineer, etc. l2mo. . . 75 cts. 
SMITH. — A Manual of Political Economy. 

By E. Peshine Smith. A New Edition, to which is added a full 

Index. i2mo. ^l 25 



HENRY CAREY LAIRD & CO.'S CATALOGUE. 25 

SMITH. — Parks and Pleasure - Grounds : 

Or Practical Notes on Country Residences, Villas, Public Parks, and 
Gardens. By Charles H. J. Smith, Landscape Gardener and 
Garden Architect, etc., etc. l2mo. .... ;j2.oa 

SMITH.— The Dyer's Instructor: 

Comprising Practical Instructions in the Art of Dyeing Silk, Cotton, 
Wool, and Worsted, and Woolen Goods ; containing nearly 800 
Receipts. To which is added a Treatise on the Art of Padding; an^ 
the Printing of Silk Warps, Skeins, and Handkerchiefs, and the^ 
various Mordants and Colors for the different styles of such work. 
By David Smith, Pattern Dyer. i2mo. . . . ^1.50 

SMYTH. ^A Rudimentary Treatise on Coal and Coal-Mining. 
By Warrington W. Smyth, M. A., F. R. G., President R. G. S, 
of Cornwall. Fifth edition, revised and corrected. With numer- 
ous illustrations. l2mo. ...... ^I»7S 

SNIVELY. — Tables for Systematic Qualitative Chemical AnaK 
ysis. 
By John H. Snively, Phr. D. 8vo. . . . . $1.00 

SNIVELY. — The Elements of Systematic Qualitative tL-hemical 
Analysis : 
A Hand-book for Beginners. By John H. Snively, Phr. D. i6mo. 

^2.00 

STOKES. — The Cabinet Maker and Upholsterer's Companion: 
Comprising the Art of Drawing, as applicable to Cabinet Work; 
Veneering, Inlaying, and Buhl- Work; the Art of Dyeing and Stain 
ing Wood, Ivory, Bone, Tortoise-Shell, etc. Directions for Lacker 
ing. Japanning, and Virnishing; to make French Polish, Glues 
Cements, and Compos'..-' ns; with numerous Receipts, useful to work 
men generally. Bv Stokes. Illustrated. A New Edition, with 
an Appendix upor ..ench Polishing, Staining, Imitating, Varnishing, 
etc., etc. i2mo ^1.25 

STRENGTH AND OTHER PROPERTIES OF METALS: 
Reports of Experiments on the Strength and other Properties of 
Metals for Cannon. With a Description of the Machines for Testing 
Metals, and of the Classification of Cannon in service. By Officers 
of the Ordnance Department, U. S. /irmy. By authority of the Secre- 
tary of War. Illustrated by 25 large steel plates. Quarto . ^S-OO 

SULLIVAN. — Protection to Native Industry. 

By Sir Edward Sullivan, Baronet, author of "Ten Chapters on 
Social Reforms." 8vo. ....... ^i.oo 

SHERRATT.— The Elements of Hand-Railing: 

Simplified and Explained in Concise Problems that are Easily Under- 
stood. The whole illustrated with Thirty-eight Accurate and Origi- 
nal Plates, Founded on Geometrical Principles, and Showing how to 
Make Rail Without Centre Joints, Making Better Rail of the Same 
Material, with Half the Lal)or, and Showing How to Lay Out Stairs 
of all Kinds. By R. J. Sherratt. Folio. . . . ;5!2.5o 



26 HENRY CAREY BAIRt? & CO.'S CATALOGUE. 

SYME. — Outlines of an Industrial Science. 
By David Syme. i2mo. . . ... ;j2.oo 

TABLES SHOWING THE WEIGHT OF ROUND, 
SQUARE, AND FLAT BAR IRON, STEEL, ETC., 

By Measurement. Cloth ...... 63 

TAYLOR.— Statistics of Coal: 

Including Mineral Bituminous Substances employed in Arts and 
Manufactures; with their Geographical, Geological, and Commercial 
Distribution and Amount of Production and Consumption on the 
American Continent. With Incidental Statistics of the Iron Manu- 
facture. By R. C. Taylor. Second edition, revised by S. S. Halde* 
MAN. Illustrated by five Maps and many wood engravings. 8vo., 
cloth ^6.00 

TEMPLETON. — The Practical Examinator on Steam and the 

Steam-Engine: 

With histructive References relative thereto, arranged for the Use of 

Engineers, Students, and others. By William Templeton, En. 

gineer. i2mo. ........ ^i.oo 

THAUSING.— The Theory and Practice of the Preparation of 
Malt and the Fabrication of Beer: 
With especial reference to the Vienna Process of Brewing. Elab- 
orated from personal experience by Julius E. Thausing, Professor 
at the School for Brewers, and at the Agricultural Institute, Modling, 
near Vienna. Translated from the German by WiLLIAM T. BraNNT, 
Thoroughly and elaborately edited, with much American matter, and 
according to the latest and most Scientific Practice, by A. ScHWARZ 
and Dr. A. H. Bauer. Illustrated by 140 Engravings. 8vo., 815 
pages ^lo.oo 

THOMAS. — The Modern Practice of Photography: 

By R. W. Thomas, F. C. S. 8vo. .... 25 

THOMPSON.— Political Economy. With Especial Reference 
to the Industrial History of Nations : 
By Robert E. Thompson, M. A., Professor of Social Science in the 
University of Pennsylvania. l2mo. .... ^1.50 

THOMSON.— Freight Charges Calculator: 

By Andrew Thomson, Freight Agent. 24mo. . . #1.25 

TURNER'S (THE) COMPANION: 

Containing Instructions in Concentric, Elliptic, and Eccentric Turn, 
ing; also various Plates of Chucks, Tools, and Instruments; and 
Directions for using the Eccentric Cutter, Drill, Vertical Cutter, and 
Circular Rest; with Patterns and Instructions for working them. 
I2mo ^I.OO 

TURNING: Specimens of Fancy Turning Executed on the 

Hand or Foot- Lathe : ( 

With Geometric, Oval, and Eccentric Chucks, and Elliptical Cutting 

Frame. By an Amateur. Illustrated by 30 exquisite Photographs. 

4to $2.50 



HENRY CAREY BAIRD & CO.'S CATALOGUE. 27 



VAILE.— Galvanized- Iron Cornice-Worker's Manual: 

Containing Instructions in Laying out the Difl'erent Mitres, and 
Making Patterns for all kinds of Plain and Circular Work. Also, 
Tables of Weights, Areas and Circumferences of Circles, and other 
Matter calculated to Benefit the Trade. By Charles A. Vaile. 
Illustrated by twenty-one plates. 4to ^5.00 

VILLE. — On Artificial Manures : 
Their Chemical Selection and Scientific Application to Agriculture. 
A series of Lectures given at the Experimental Farm at Vincennes, 
during 1867 and 1874-75. By M. Georges Ville. Translated and 
Edited by WiLLlAM Crookes, F. R. S. Illustrated by thirty-one 
engravings. 8vo., 450 pages ^6.00 

VILLE. — The School of Chemical Manures : 
Or, Elementary Principles in the Use of Fertilizing Agents. From 
the French of M. Geo. Ville, by A. A. Fesquet, Chemist and En- 
gineer. With Illustrations. i2mo. .... ^1.25 

VOGDES. — The Architect's and Builder's Pocket -Companion 
and Price-Book : 

Consisting of a Shoit but Comprehensive Epitome of Decimals, Duo- 
decimals, Geometry and Mensuration ; with Tables of United States 
Measures, Sizes, Weights, Strengths, etc., of Iron, Wood, Stone, 
Brick, Cement and Concretes, Quantities of Materials in given Sizes 
and Dimensions of Wood, Brick and Stone; and full and complete 
Bills of Prices for Carpenter's Work and Painting ; also, Rules for 
Computing and Valuing Brick and Brick Work, Stone Work, Paint- 
ing, Plastering, with a Vocabulary of Technical Terms, etc. By 
Frank W. Vogdes, Architect, Indianapolis, Ind. Enlarged, revised, 
and corrected. In one volume, 368 pages, full-bound, pocket-book 

form, gilt edges $2.00 

Cloth . . 1.50 

VAN CLEVE.— The English and American Mechanic : 
Comprising a Collection of Over Three Thousand Receipts, Rules, 
and Tables, designed for the Use of every Mechanic and Manufac- 
turer. By B. Frank Van Cleve. Illustrated. 500 pp. i2mo. ^2.00 

WAHNSCHAFFE.— A Guide to the Scientific Examination 
of Soils : 
Comprising Select Methods of Mechanical and Chemical Analysis 
and Physical Investigation. Translated from the German of Dr. F. 
Wahnschaffe. With additions by William T. Brannt. Illus- 
trated by 25 engravings. i2mo, 177 pages . , . ^1.50 

WALL. — Practical Graining : 

With Descriptions of Colors Employed and Tools Used. Illustrated 
by 47 Colored Plates, Representing the Various Woods Used Jt 
Interior Finishing. By William E. Wall. 8vo. . ^^2.50 

WALTON. — Coal-Mining Described and Illustrated: 
By Thomas H. Walton, Mining Engineer. Illustrated by 24 Jarge 
and elaborate Plates, after Actual Workings and Apparatus. #5.00 



28 HENRY CAREY BAIRD & CO.'S CATALOGUE. 

?VARE.— The Sugar Beet. 
Including a History of the Beet Sugar Industry in Europe, Varietiei 
of the Sugar Beet, Examination, Soils, Tillaj^'e, Seeds and Sowing, 
Yield and Cost of Cultivation, Harvesting, Transportation, Conserva 
tion, Feeding Qualities of the Beet and of the Pulp, etc. By Lewu 
S. Ware, C. E., M. E. Illustrated by ninety engravings. 8vo. 

WARN.— The Sheet-Metal Worker's Instructor: 

For Zinc, Sheet-Iron, Copper, and Tin- Plate Workers, etc. Contain- 
inj^ a selection of Geometrical Proh'.ems ; also. Practical and Simple 
Rules for Describing the various Patterns required in the different 
branches of the above Trades. By Reuben H. Warn, Practical 
Tin- Plate Worker. To which is added an Appendix, containing 
Instructions for Boiler-Making, Mensuration of Surfaces and Solids, 
Rules for Calculating the Weights of different Figures of Iron and 
Steel, Tables of the Weights of Iron, Steel, etc. Illustrated by thirty- 
two Plates and thirty-seven Wood Engravings. Svo. . $3.00 

WARNER. — New Theorems, Tables, and Diagrams, for the 
Computation of Earth-work : 

Designed for the u>e ol Engineers in Preliminary and Final Estimates 
of Students in Engineering, and of Contractors and other non-profes. 
sional Computers. In two parts, with an Appendix. Parti. A Prac- 
tical Treatise; Part II. A Theoretical Treatise, and the Appendix. 
Containing Notes to the Rules and Examples of Part I.; Explana- 
tions of the Construction of Scales, Tables, and Diagrams, and 3 
Treatise upon Equivalent Square Bases and Equivalent Level Heights. 
By John Warner, A. M., Mining and Mechanical Engineer. Illus- 
trated by 14 Plates. Svo. I400 

WILSON. — Carpentry and Joinery : 

By lOHN Wilson, Lecturer on Building Construction. Carpentry and 
Joinery, etc., in the Manchester Technical Sciiool. Third Edition, 
with 65 full page plates, in flexible cover, oblong . . .80 

WATSON. — A Manual of the Hand-Lathe : 

Comprising Concise Directions for Working Metals of all kinds. 
Ivory, Bone and Precious Woods; Dyeing, Coloring, and French 
Polishing; Inlaying by Veneers, and various methods practised tc 
produce Elaborate work with Dispatch, and at Small Expense. By 
Egbert P. Watson, Author of " The Modern Practice of American 
Machinists and Engineers." Illustrated by 78 engravings. $1.50 

WATSON.— The Modern Practice of American Machinists and 
Engineers 
Including the Construction, Application, and Use of Drills, Latvia 
Tools, Cutters for Boring Cylinders, and Hollow-work generally, with 
the most Economical Speed for the same; the Results verified bj 
Actual Practice at the Lathe, the ^-Hse, and on the Floor. Together 



1 



HENRY CAREY BAIRD & CO.'S CATALOGUE. 29 

with Workshop Management, Economy of Manufacture, the Steam 
Engine, Boilers, (Jears, Behing, etc., etc. By Egbert P. Watson. 
lliiistra ed by eighty-six engravings. i2mo. . . . ^2.50 

WATT.— The Art of Soap Making : 

A Practical lland-Book ol tlie Manufacture of Hard and Soft Soaps, 
Toilet Soaps, etc. Fifth Edition, Revised, to which is added an 
Appendix on Modern Candle Making. By ALEXANDER Watt. 
111. l2mo S3.00 

WEATHERLY.— Treatise on the Art of Boiling Sugar, Crys- 
tallizing, Lozenge-making, Comfits, Gum Goods, 
Anil other processes for Confectionery, etc., in which are exjslained, 
in an easy ami familiar manner, the various Methods of Manufactur- 
ing every Description of Raw and Refined Sugar Goods, as sold by 
Confectioners and otliers. l2mo. ..... ^1.50 

WILL. — Tables of Qualitative Chemical Analysis : 

With an Introductory Cliapter on the Course of Analysis. By Pro- 
fessor Heinrich Will, of Giessen, Germany. Tiiird American, 
from the eleventh German edition. Edited by Charles F. Himes, 
Ph. D., Professor of Natural Science, Dickinson College, Carlisle, 
Pa. 8vo ^1.50 

WILLIAMS.— On Heat and Steam : 

Embracing New Views of Va|)orization, Conden.^ation and Explo- 
sion. By Charles Wye Williams, A. I. C. E. Illustrated. 8vo. 

^2.50 

WILSON. — First Principles of Political Economy: 

Witli Reference to Statesmanship and the Progress of Civilization. 
By Professor W. D. Wilson, of the Cornell University. A new and 
revised edition. i2mo. ....... $I-50 

WILSON.— The Practical Tool-Maker and Designer: 

A Treatise upon the Designing of Tools and Fixtures for Machine 
Tools and Metal Working Macliinery, Comprising Modern Examples 
of Machines with Fundamental Designs for Tools for the Actual Pro- 
ducdon of the work; Together with Special Reference to a Set of 
Tools for Machining the Various Parts of a Bicycle. Illustrated by 
189 engravings. 1898. ....... $2.50 

CONTENTS: Introductory. Chapter I. Modern Tool Room and Equipment. 
II. Files, I'hcir Use and Abuse. III. Steel ;iiid Tempering. IV. Making Jigs. 
v. Milling Machine Hixtures. VI. Tools and Fixtures for Screw Machines. VII. 
Bro.iching. VIII. Punches and Dies for Cutiing and Drop Press. IX. Tools for 
Hollow-Ware. X Embossing: Metal, Com, and Stainped Sheet-Metal Orna- 
ments. XI. Drop Forging XII. Solid Drawn Slulls or Ferrules: Cupping or 
Cutting, and Drawing : Breaking Down Shells XIII. Annealing, Pickling and 
Cleaning. XIV. Tools for Draw Bench. XV. Cutting and Assembling Pieces 
by Means of Ratchet Dial Plates at One Operation. XVI. The Header. XVII. 
Tools for Fox Lathe. XVIII Suggestions lor a Set of Tools for Machining the 
Viirious Parts of a Bicycle. XIX. The Plater's Dynamo. XX. Conclusion — 
With a Few Random Ideas. Appendix. Index. 

WOODS. — Compound Locomotives: 

l>y Arthur Tannatt Woods. Second edition, revised and enlarged 
by David Leonard Barnes, A. M., C. E. 8vo. 330 pp. ;5!3 00 



JO HENRY CAREY BAIRD & CO.'S CATALOGUE. 

WOHLER. — A Hand-Bookof Mineral Analysis: 

By F. WoHLER, Professor of Chemistry in the University of Gottin- 
gen. Edited by Henry B. Nason, Professor of Chemistry in the 
Renssalaer Polytechnic Institute, Troy, New York. Illustrated. 
i2mo ^2.50 

WORSSAM. — On Mechanical Saws: 

From the Transactions of the Society of Engineers, 1869. By S. W. 
WuRsSAM, Jr. Illustrated by eighteen large plates. 8vo, $i'S^ 



RECENT ADDITIONS. 

BRANNT. — Varnishes, Lacquers, Printing Inks and Sealing* 
Waxes : 

Their Raw Materials and their Manufacture, to which is added the 
Art of Varnishing and Lacquering, including the Preparation of Put- 
ties and of Stains for Wood, Ivory, Bone, Horn, and Leather. By 
William T. Brannt. Illustrated by 39 Engravings, 338 pages. 

i2mo ^3.00 

BRANNT — The Practical Scourer and Garment Dyer: 

Comprising Dry or Chemical Cleaning ; the Art of Removing Stains , 
Fine Washing ; Bleaching and Dyeing of Straw Hats, Gloves, and 
Feathers of all kinds; Dyeing of Worn Clothes of all fabrics, in- 
cluding Mixed Goods, by One Dip; and the Manufacture of -Soaps 
and Fluids for Cleansing Purposes. Edited by William T. Brannt, 
Editor of "The Techno-Chemical Receipt Book." Illustrated 
203 pages. i2mo. ....... $2.00 

BRANNT.— Petroleum . 

its History, Origin, Occurrence, Production, Physical and Chemical 
Constitution, Technology, Examination and Uses; Together with 
the Occurrence and Uses of Natural Gas. Edited chiefly from the 
German of Prof. Hans Hoefer and Dr. Alexander Veith, by Wm. 
T. Brannt. Illustrated by 3 Plates and 284 Engravings. 743 pp. 
8vo. $j.^o 

BRANNT.— A Practical Treatise on the Manufacture of Vine- 
gar and Acetates, Cider, and Fruit-Wines: 
Preservation of Fruits and Vegetables by Canning and Evaporation; 
Preparation of Fruit-Butters, Jellies, Marmalades, Catchups, Pickles, 
Mustards, etc. Edited from various sources. By William T. 
Brannt. Illustrated by 79 Engravings. 479 pp. 8vo, ^5.00 

BRANNT.— The Metal Worker's Handy-Book of Receipts 
and Processes : 

Being a Collection of Chemical Formulas and Practical Manipula- 
tions for the working of all Metals ; including the Decoration and 
Beautifying of Articles Manufactured therefrom, as well as their 
Preservation. Edited from various sources. By William T. 
Brannt. Illustrated. i2mo. 52.50 



HENRY CAREY BAIRD & CO.'S CATALOGUE. ^t 

DFITE.— A Practical Treatise on the Manufacture cf Per- 

turnery: 

Comprising directions for making all kinds of Perfumes, Sachet 

Powders, Fumigatincr Materials, Dentifrices, Cosmetics, etc., with a 

full account of the A'ulatile Oils, Balsams, Resins, and other Natural 

and Artificial Perfume-substances, including the Manufacture of 

Fruit Ethers, and tests of their purity. By Dr. C. Deite, assisted 

by L. BoRCHERT, F. Eichbaum, E. Kugler, H. Toeffner, and 

other expeits. From the German, by Wm. T. Brann r. 28 Engrav 

mgs. 358 pages. 8vo. . . • . . . . $3.00 

EDWARDS. — American Marine Engineer, Theoretical ar.L. 

Practical : 

With Examples of the latest and most approved American Practice. 

By Emory Edwards. 85 illustrations. i2mo. . . $2.50 

EDWARDS. — 900 Examination Questions and Answers; 

For Engineers and Firemen (Land and Marine) « ho desire to ob- 
tain a United States Government or .State License. Pocket-book 
form, gilt edge ......-• ^i-5° 

KIRK.— The Cupola Furnace: 

A Practical Treatise on the Construction and Management of Foun- 
dry Cupolas. By Edward Kirk, Practical Moulder and Melter, 
author of "The Founding of Metals." Illustrated by So Engravings. 
8vo. (In Preparation.) 

POSSELT.— The Jacquard Machine Analysed and Explained: 

With an Appendix on the Preparation of Jacquaid Cards, and 
Practical Hints to Learners of Jacquard Designing. By E. A. 
Posselt. With 230 illustrations and numerous diagrams. 127 pp. 
4to. ij.oa 

POSSELT.— The Structure of Fibres, Yarns and Fabrics: 

Being a Practical Treatise for the Use of all Persons Employed in 
the Manufacture of Textile Fabrics, containing a Description of the 
Growth and Manipulation of Cotton, Wool, Worsted, Silk Flax, 
Jute, Ramie, China Grass and Hemp, and Dealing with all Manu- 
facturers' Calculations for Every Class of Material, also Giving, 
Minute Details for the Structure of all kinds of Textile Fabrics, and 
an Appendix of Arithmetic, specially adapted for Textile Purposes. 
By E. A. Posselt. Over 400 Illustrations, quarto. . ^500 

RICH. — Artistic Horse-Shoeing: 

A Practical and Scientific Treatise, giving Improved Methods of 
Shoeing, with Special Directions for Shaping Shoes to Cure Different 
Diseases of the Foot, and for the Correction of Faulty Action in 
Trotters. By George E. Rich. 62 Illustrations. 153 pages. 

. l2mo ^i.oo 



32 HENRY CAREY BAIRD & CO.'S CATALOGUE. 

RICH ARDSON.— Practical Blacksmithing : 

A CoUeciion of Articles Contributed at Different Times by Skilled 
Workmen to the columns of " The Blacksmith and Wheelwright," 
and Covering nearly the Whole Range of Blacksmithing, from the 
Simplest Job of Work to some of the Most Complex Forgings. 
Compiled and Edited by M. T. Richardson. 

Vol. I. 2IO Illustrations. 224 pages. l2mo. . . $1.00 

Vol.11. 230 Ilkistrations. 262 pages. i2mo. . . ^100 
Vol. III. 390 Illustrations, 307 pages. i2mo. . . $1 00 

Vol. IV. 226 Tllu-trati£)ns. 276 pages. i2mo. . . $i.f'-> 

RICHARDSON —The Practical Horseshoer: 
Being a Collection of Articles on Horseshoeing in all its Branches 
which have appeared from time to time in the columns of " '] he 
Blacksmith and Wheelwright," etc. Compiled and edited by M. T. 
Richardson. 174 illustrations ^i.oo 

ROPER. — Instructions and Suggestions for Engineers and 
Firemen : 
By Stephen Roper, Engineer. iSmo. Morocco . $2.00 

ROPER. — The Steam Boiler: Its Care and Management: 
By Stephen Roper, Engineer. i2mo., tuck, gilt edges. ^2.00 

ROPER. — The Young Engineer's Own Book: 

Containing an Explanation of the Principle and Theories on which 
the Steam^Engine as a Prime Mover is Based. By Stephen Roper, 
Engineer. 160 ijlustrations, 363 pages. iSmo., tuck . ^2 50 

ROSE. — Modern Steam- Engines: 

An Elementary Treatise upon the Steam-Iingine, written in Plain 
language ; for Use in the Workshop as well as in the Drawing Office. 
Giving Full Explanations of the Construction of Modern Steanrv 
Engines: Including Diagrams showing their Actual operation. To- 
gether with Complete but Simple Ex|ilanations of the operations of 
Various Kinds of Valves, Valve Motions, and Link Motions, etc., 
thereby Enabling the Ordinary Engineer to clearly Understand the 
Principles Involved in their Construction and Use, and to Plot out 
their Movements upon the Drawing Board. By Joshua Rose. M. E. 
Illustrated by 422 engravings. Revised. 358 pp. . . ^6.00 

ROSE. — Steam Boilers: 

A Practical Treatise on Boiler Construction and Examination, for the 
Use of Practical Boiler Makers, Boiler Users, and Inspectors; and 
embracing m plain figures all the calculations necessary in Designing 
or Classifying Steam ^Boilers. By JosHUA Rose, M. E. Illustrated 
by 73 engravings. 250 pages. 8vo. . . . . t?2 1^0 

:JCHRIBER.— The Complete Carriage and Wagon Painter: 
A Concise Compendium of the Art of Painting Carnages, Wag;ms, 
and Sleighs, embracing Full Directions in all the Various Branches, 
including Lettering, Scrolling, Ornanjenting, .Striping, Varnishing, 
and Coloring, with numerous Recipes for Mixing Colors. 73 lllus- 
tvatjons. 177 pp. l2mo. ...••• ^i-OO 



MAR IS ^859 



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